How to add a logo on the bar?

To change the shape of the bar the following steps:

Step 1: Select "Styles" on the left panel
Step 2: Click on any style.
Step 3: Click on the "Customize your style" button.
Step 4: Select "Logo" under Stickers title.

To change the logo the following steps:

Step 1: Select "Settings" on the left panel
Step 2: Click on the "Logo settings" tab
Step 3: Click on the "Change" button.