A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
If the folder is shared with "Anyone in your organization" and the files inherit permissions (the default behavior), then any new files you add to that folder will automatically inherit the folder's permissions. You do not need to set permissions on each individual file.
This only changes if inheritance has been broken on a specific file or if someone manually assigns unique permissions to a file after it is uploaded. In that case, that file can have different access than the rest of the folder.
More at https://learn.microsoft.com/en-us/sharepoint/understanding-permission-levels
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hth
Marcin