Use your font in
A font file is only useful once it is inside the app you actually use. One short guide per app, including the honest ones where the answer is a workaround.
GoodNotes
Use your own handwriting as a typed font in GoodNotes. Install the font on your iPad or iPhone and it shows up in the text tool's font list.
Notability
Type in your own handwriting in Notability. Install the SnapFont font on your iPad or iPhone and pick it in the text tool.
Procreate
Add your handwriting font to Procreate on iPad: import the TTF with the text tool's Import Font button, or install it system-wide and pick it from the list.
Cricut Design Space
Use your own handwriting font in Cricut Design Space for vinyl, cards, and labels. Install the TTF on your computer, or the profile on your iPhone or iPad, and it appears under System fonts.
Microsoft Word
Type in your own handwriting in Microsoft Word on Windows, Mac, iPhone, or iPad. Install the font and it appears in Word's font list.
Google Docs
Google Docs cannot use custom fonts, including your own handwriting font. Here is what it can do, and three ways around it.
Canva
Upload your handwriting font to Canva through Brand Kit. It needs Canva Pro, Teams, or Education; here is the exact path and a free workaround.
iPhone
Install your handwriting font on iPhone without a computer. SnapFont builds the configuration profile; you approve it in Settings.
iPad
Install your handwriting font on iPad the same way as iPhone, then use it in GoodNotes, Notability, Procreate, Pages, and Keynote.
Android
Android cannot install fonts system-wide. SnapFont exports your handwriting font as a TTF, and here is where that file can actually be used.
Photoshop
Use your handwriting font in Photoshop on Windows or Mac. Install the TTF and it appears in the Type tool's font list.
Obsidian
Set your handwriting font as the text font in Obsidian on desktop or mobile, or apply it to just headings with a small CSS snippet.