Requiring Check-in of Documents in a library

[RobertB1270]

How do I require each time someone uploads a file to the library, they have to enter the meta-data required before it is uploaded (similar to making a list entry). Using classic SharePoint, I remember the functionality. I currently use modern SharePoint and I cannot find any help for requiring this.

[#2]

Hello @RobertB1270 

you mean a pop-up when you upload a file, right?!

This is not available, i think, the pop-up appears only when you upload a sinlge document and you use mandatory fields in the classic library.

In modern you can use version settings (main and draft) and you can use mandatory fields in your library...same like in classic. A pop-up is not appears in modern, but the information panel will open when you upload a single document:

As additional feature in modern you have a view "Files that need attention", with the new uploaded files without mandatory metadata...

Hope this helps.

Best, Dave

[#3]

@RobertB1270 
@David Mehr is correct.

The modern view allows uploading of files with required columns and if the user does not set value(s) the files are listed "Files that need attention". 

It is up to the user to provide values. This may not always happen.

The classic view does offer this capability but you solve one problem and introduce new ones.

There are also 3rd apps that offer this capability (ensure the user enters values for required columns). See list with apps (link).