You can create a value question to allow your customers decide whether or not they want a logo.
Create a logo question
Start by creating a logo question.
Name it 'My Logo'.
Creating an 'Add a logo?' question
Click on the + button in the top left part of the screen.
Under Select input type, you can select Thumbnail, Dropdown or Radio or Label.
Under Select a display type, pick None, then hit Create.
From the right side panel, under Title, name your question 'Add a logo?'.
Adding 'yes' or 'no' answers
Once your question is created, you can add 'yes' and 'no' answers.
Open your question. Within the right side panel, next to Value answers, hit the + button.
Under Title, type 'Yes' and hit Create.
Repeat this process to add a 'No' value answer.
Creating a rule to hide the logo when 'no' is selected
On the top right of the screen, click on Logic.
Click on + Add rule.
Create a rule like this one :
When Add a logo? is No then My Logo should be unavailable.
Activate the hide when empty setting (barebones theme)
If you are using the Barebones theme and you wish to hide the Logo question when it's not available, make sure to enable the 'Hide when empty' setting.