django_admin_form.py

from django.db import models
from django.forms import Textarea

class HowToItemInline(admin.StackedInline):    
    # All fields of a particular type
    formfield_overrides = {
        models.TextField: {"widget": Textarea(attrs={"rows": 1, "cols": 80})},
    }
    
    # Specific fields
    wide_charfields = ["field1", "field2"]  

    def get_formset(self, request, obj=None, **kwargs):
        formset = super().get_formset(request, obj, **kwargs)
        for field in self.wide_charfields:
            formset.form.base_fields[field].widget = Textarea(attrs={"rows": 2, "cols": 80})
        return formset
        
class HowToAdmin(admin.ModelAdmin):     
    # All fields of a particular type
    formfield_overrides = {
        models.TextField: {"widget": Textarea(attrs={"rows": 1, "cols": 80})},
    }
    
    # Specific fields
    wide_charfields = ["field1", "field2"]

    def get_form(self, request, obj=None, **kwargs):
        form = super().get_form(request, obj, **kwargs)
        for field in self.wide_charfields:
            form.base_fields[field].widget = Textarea(attrs={"rows": 1, "cols": 80})
        return form