maya_popup_test.py

from PySide2.QtCore import *
from PySide2.QtGui import *
from PySide2.QtWidgets import *
from pymel.core import *


text = '''<h2>Title</h2>
Some text

<a href="https://google.com">Help</a>
'''
lb = QLabel(ui.PyUI('MayaWindow').asQtObject())
lb.setTextInteractionFlags(Qt.TextBrowserInteraction)
lb.setOpenExternalLinks(True) 
lb.setMinimumWidth(500)
lb.setStyleSheet('''
QWidget{
    background-color: #ffffdb;
    color:black;
    padding: 10px 10px 10px 10px;
}
''')

lb.setWindowFlags(Qt.ToolTip)
lb.setText(text.replace('\n', '<br>'))
lb.show()

# lb.close()