How do I type into an existing fillable PDF?
The problem: When I open a fillable PDF, Draw automatically opens it in edit mode. That makes it impossible to type into fillable boxes and lines. When I ask for help, all Help files discuss how to create a fillable PDF and none discuss how to type into an existing fillable PDF.
There is hardly ever any reason to open any PDF with LibreOffice. Just open the PDF with your favorite PDF viewer. No, it does not need to be Adobe Acrobat.
If your goal is to use the fillable PDF to submit an application to the issuing body, use a PDF reader.
You didn’t mention your OS name, so I can only suggest “generic” portable readers like Adobe Acrobat Reader but others are possible depending on your platform.