If you noticed something is missing before you file your return you should add it manually and then keep going.

If you noticed something is missing after you've already filed you'll need to make the change in Better Tax and then ReFILE your return. If it's been awhile since you ran Auto-fill My Return, you might want to rerun it to see if the slip is now available. If not, you can add it manually.

How to add something manually

If you have a copy of your slip or receipt, but you have a paper or digital copy, search for it in Better Tax (e.g., "T4" or "donation") and enter the information manually. If it's something that shows up in Auto-fill My Return later, like a T3, you'll have the option to replace that slip when you re-run Auto-fill My Return.

If you don't have a copy of the slip or receipt, you'll need to ask the slip issuer (like your employer, bank, etc.) for a copy.