Drupal 8.x

I had my site in D7 that I successfully upgraded to D9.

Now I want to add a text (string) field to user record. I understand that I can add that field using admin GUI. However I have following questions.

How do I add/update this new text string to all the existing user records (around 20000) programmatically?

I want only Admin should be able to read/write this string. How is this achieved?

Please let me know/point me to any already existing doc for this.

Please let me know If I should add more details here.

Thanks

I created contact-webform. It contains a Captcha-field. But this field is not shown when the contact-webform is selected. Have a look at: https://files.fm/u/g74jvcbh4

Can someone help me? Thank you very much!

I've upgraded a site from Drupal 7 to Drupal 8. I did it manually, not using composer. So I downloaded the zip core tarball, and then installed modules manually (the old way, by downloading and extracting modules in modules/contrib and enabling them in "Extend" in the admin of the site). The site is working perfectly. The "status report" shows no errors and just one non-relevant warning. I seem to have read that composer was the recommended way but the old procedure could still be used.

I'm running the newest version of Drupal 8 and I wonder how to upload webP images?

In particular, I have a slider module that says "The selected file xyz.webp cannot be uploaded. Only files with the following extensions are allowed: gif, png, jpg, jpeg, svg."

Then, there is the CKeditor plugin which says the same.

I could not the setting in Drupal to specify allowed file formats for upload - where is it?

Hi,

I'm unable to update to above release via composer.

When I type composer update drupal/core-recommended --with-dependencies I get a message saying

Hi every one,
I have an Idea and I think I can do it with Drupal. but not sure is it possible in drupal or not.
I want to have some subuser system but not like subuser module.
My Idea is a user after registration will complete profile. this user can assign the profile he/she made to another one. once it done profile page of user will be read only to him/her and only other user which have permission can edit the profile and only second user can unassigned profile and give editing permission back to the creator.