Create PDF & Add Content to PDF, Modify PDF Document and Create PDF Forms in JavaScript using pdf-lib Library. Check https://products.documentprocessing.com/editor/javascript/pdf-lib/ for more details.

create-pdf-and-add-content-to-pdf-in-javascript-using-pdf-lib-library.js

// Import required objects and functions from pdf-lib library
import { PDFDocument, StandardFonts, rgb } from 'pdf-lib';

// Import fs module from Node.js standard library
import fs from 'fs/promises';

// Asynchronously create a PDF document
async function createPdf() {

 // Create a new PDF document
 const pdfDoc = await PDFDocument.create();

 // Embed the Times Roman font
 const timesRomanFont = await pdfDoc.embedFont(StandardFonts.TimesRoman);

 // Add a new page to the PDF document
 const page = pdfDoc.addPage();
 const { width, height } = page.getSize();
 const fontSize = 30;

 // Draw text on the page
 page.drawText('Creating PDFs in JavaScript is awesome!', {
 x: 50,
 y: height - 4 * fontSize,
 size: fontSize,
 font: timesRomanFont,
 color: rgb(0, 0.53, 0.71),
 });

 // Save the PDF document to a byte array
 const pdfBytes = await pdfDoc.save();

 // Write the byte array to an 'output.pdf' file
 await fs.writeFile('output.pdf', pdfBytes);
 console.log(`PDF saved`);
}

// Call the createPdf function to generate and save the PDF
createPdf();

create-pdf-forms-in-javascript-using-pdf-lib-library.js

// Import PDFDocument object from pdf-lib library
import { PDFDocument } from 'pdf-lib';

// Import fs module from Node.js standard library
import fs from 'fs/promises';

async function createForm() {
  // Create a new PDF document
  const pdfDoc = await PDFDocument.create();

  // Add a page with dimensions 550x750
  const page = pdfDoc.addPage([550, 750]);

  // Access the form in the PDF document
  const form = pdfDoc.getForm();

  // Add text to the page
  page.drawText('Enter your favorite superhero:', { x: 50, y: 700, size: 20 });

  // Create and add a text field for the favorite superhero
  const superheroField = form.createTextField('favorite.superhero');
  superheroField.setText('One Punch Man');
  superheroField.addToPage(page, { x: 55, y: 640 });

  // Add more text and create a radio group for favorite rockets
  page.drawText('Select your favorite rocket:', { x: 50, y: 600, size: 20 });
  page.drawText('Falcon Heavy', { x: 120, y: 560, size: 18 });

  // Create and add a radio group for favorite rockets
  const rocketField = form.createRadioGroup('favorite.rocket');
  rocketField.addOptionToPage('Falcon Heavy', page, { x: 55, y: 540 });
  rocketField.addOptionToPage('Saturn IV', page, { x: 55, y: 480 });
  rocketField.select('Saturn IV');

  // Create and add checkboxes for favorite gundams
  const exiaField = form.createCheckBox('gundam.exia');
  const kyriosField = form.createCheckBox('gundam.kyrios');

  // Check specific checkboxes
  exiaField.check();
  dynamesField.check();

  // Create and add a dropdown for favorite planets
  const planetsField = form.createDropdown('favorite.planet');
  planetsField.addOptions(['Venus', 'Earth', 'Mars', 'Pluto']);
  planetsField.select('Pluto');
  planetsField.addToPage(page, { x: 55, y: 220 });

  // Create and add an option list for favorite persons
  const personField = form.createOptionList('favorite.person');
  personField.addOptions([
    'Julius Caesar',
    'Ada Lovelace',
    'Cleopatra',
    'Aaron Burr',
    'Mark Antony',
  ]);

  personField.select('Ada Lovelace');
  personField.addToPage(page, { x: 55, y: 70 });

  // Add a note about Pluto
  page.drawText(`* Pluto should be a planet too!`, { x: 15, y: 15, size: 15 });

  // Save the PDF document
  const pdfBytes = await pdfDoc.save();

  // Write the PDF to a file
  await fs.writeFile("form.pdf", pdfBytes);
}

// Call the createForm function to create the form and save it as 'form.pdf'
createForm()
  .then(() => {
    console.log('Form Created');
  })
  .catch((error) => {
    console.error('Error in creating form', error);
  });

modify-pdf-document-in-javascript-using-pdf-lib-library.js

// Import required objects and functions from pdf-lib library
import { degrees, PDFDocument, rgb, StandardFonts } from 'pdf-lib';

// Asynchronously modify a PDF document
async function modifyPdf() {

  // Load the input PDF from a local file
  const filePath = 'documentprocessing.pdf'; file name
  const existingPdfBytes = await fs.readFile(filePath);

  // Load PDF document from the binary data and embed Helvetica font into it asynchronously
  const pdfDoc = await PDFDocument.load(existingPdfBytes);
  const helveticaFont = await pdfDoc.embedFont(StandardFonts.Helvetica);

  // Get all pages of the PDF document
  const pages = pdfDoc.getPages();

  // Get first page of the PDF
  const firstPage = pages[0];

  // Get the height & width of the first page of the PDF
  const { width, height } = firstPage.getSize();

  // Add diagonal red text to the first page
  firstPage.drawText('This text was added with JavaScript!', {
    x: 5,
    y: height / 2 + 300,
    size: 50,
    font: helveticaFont,
    color: rgb(0.95, 0.1, 0.1),
    rotate: degrees(-45),
  });

  // Save changes to the PDF document as binary data
  const modifiedPdfBytes = await pdfDoc.save();

  // Save the modified PDF in binary form to a file
  await fs.writeFile("modified-pdf.pdf", modifiedPdfBytes);
}

// Call the modifyPdf function to modify and save the PDF
modifyPdf()
  .then(() => {
    console.log('PDF modification complete');
  })
  .catch((error) => {
    console.error('Error modifying PDF:', error);
  });