event, On current
FieldName = "Your txt here"

Many ways to do this I think the best is a tech help
try this
https://599cd.com/blog/display-article.asp?ID=1636

the rest are ideas you may like to play with
https://599cd.com/blog/display-article.asp?ID=1690
https://599cd.com/blog/display-article.asp?ID=2120
https://599cd.com/blog/display-article.asp?ID=1750

V/r
Juan

In addition to what Juan recommended I'd take a look at

Appointments
and
Add Records Automatically

I cover recurring billing in Access Payables Seminar. Very similar concept.