Questions: To deposit a check using a mobile banking app, you have to upload pictures of your signed check.

The answer is the third one: upload pictures of your signed check.

Explanation for each option:

1. Check your interest rate: This is not required for depositing a check using a mobile banking app. Checking your interest rate is related to understanding the earnings on your savings or other interest-bearing accounts.
2. Have more than one account: This is not necessary for depositing a check using a mobile banking app. You can deposit a check into a single account.
3. Upload pictures of your signed check: This is the correct procedure. Mobile banking apps typically require you to take and upload photos of both the front and back of the signed check to complete the deposit.
4. Mail the check to your financial institution: This is not required when using a mobile banking app. The purpose of the app is to avoid the need to mail or physically deliver the check to the bank.

Summary: To deposit a check using a mobile banking app, you need to upload pictures of your signed check.