This post helps to add a text box to PDF using a free software and an online tool. You can adjust the size of text box, text style, etc.

LibreOffice Writer can create fillable PDFs from scratch with built-in tools. Start by opening a blank document and adding form fields using the Form Controls and Form Design toolbars. To export as an ...

If selecting to add a text box, you'll first be able to move the text box by dragging and resizing it as needed. Then you can tap into the text box to bring up the keyboard for entering text.