When using Project for the web, you have the ability to associate that project with a Microsoft 365 Group. This enables many features such as the ability to give other users access to the project and the ability to upload attachments to tasks – tasks attachments are covered here: https://pwmather.wordpress.com/2021/01/10/task-attachments-in-projectfortheweb-workmanagement-taskmanagement-ppm-msproject-microsoft365groups/. You can also use the file storage provided by SharePoint via the Microsoft 365 Group, to store all project level related files such as:
To access the collaboration space, access the project in the Project UI then click the ellipsis in the top right hand corner then click Team files on the menu as seen below:
This option is only present when the project is associated to a Microsoft 365 Group. This provides a great collaboration spaces for all of the project artefacts.
Modern Work Management - Project and the Power Platform blog 