I'm developing an e-commerce site for a client, how do they update items on the shop?

I'm developing an e-commerce site for a client, how do they update items on the shop?

I've created an e-commerce site for my client, however I'm unsure on how clients would be able to add/remove items onto the store, without the help of a developer. Are they supposed to directly edit the database, or am I supposed to create an easy to use intuitive front-end admin panel that will allow them to add/edit/remove products.

Created the e-commerce site using ReactJS, firebase + node for the back-end

This is a loaded question, as there are many ways to solve this.

1. Create a custom admin area so your client can manage products (probably a lot of additional work + authentication)
2. Give the client access to the database (not recommended, even if they're competent with the technology)
3. Implement one of the many e-commerce frameworks available that come with all of these problems already solved.

As I said, there are a lot of other solutions to this. I'd almost always go for solution 3 to keep costs and maintenance down.