After you have agreed on including a Content Management System to be able to make changes to the site yourself, you will need to be trained in how to use it.
Will the web designer give you extensive training on how to use the site once the project is delivered? Even 1 hour may not be enough to be able to understand how it works adequately.
Ask if there are online videos or instructions or a handbook you can refer to later?
If you have many items to list in your online store, make sure you know the process of uploading new products, and it’s explained in detail. Often this is done using detailed csv spreadsheets to bulk upload them, and the spreadsheet column layouts can be tricky to configure.
Again, ask the web designer to give you a quick tour around the admin section of the site before you make your final decision.
Some platforms are easier to use than others. Ask for a demonstration on how to make simple changes like adding new images, changing the text or adding a new page.