Text Replacement Feature for Usernames & Passwords?

I was REALLY hoping we could use the "text replacement" feature for Keyboards in Settings > General to get the "littles" in our schools signed into Canvas and Microsoft 365. It isn't working though. My process was this: Settings > General > Keyboards > Text Replacement > tap the + > type in a student's email address in "Phrase" section > type student's initials in "Shortcut" section > Tap Save > repeat the process for the student's password this time adding a 2 to the end of their initials > tap Save > go to Canvas LMS website > type in shortcut for student's email address > hit ENTER or TAB > (note: it did not enter student's email address - ended up typing it in) > used shortcut for student's password > (note: it did not enter student's password either). What am I doing wrong? Anyone have suggestions on how to make this work so our little ones can use Canvas and Microsoft 365?

Thank you in advance!

God bless,

Carrie Nielsen