Only let people add rows in Sharepoint list without viewing the existing rows

louisquinet 

SharePoint default permissions does not work like that.

You need Contribute or higher (Edit/Full control, etc.) permissions to create new items in the list AND with contribute permissions to SharePoint list, you can see the existing list items by default (as Contribute is higher permissions than Read). Check: SharePoint user permissions and permission levels  

Instead, you can create a Power Apps for UI and add records in SharePoint list. Then hide the SharePoint list from UI using PowerShell - this works with user permissions on the list.

Or create a Power Apps and add records in SharePoint list using admin user credentials.

Please click Mark as Best Response & Like if my post helped you to solve your issue. This will help others to find the correct solution easily. It also closes the item. If the post was useful in other ways, please consider giving it Like.