The account you designate as 'Default' will appear at the top. To sort all other accounts you'd need to install an add-on. https://addons.thunderbird.net/thunderbird/addon/manually-sort-folders/

Thank you, "Default" appears at the top now. The ad-on can probably only be used with a paid version. I have a free version.

The ad-on can probably only be used with a paid version.

How did you conclude that?

I have a free version.

Free version of what?

Because it failed to install. That will probably be my fault. I'm going to try again.

I have Thunderbird version 78.4.3 (32 bits).

Does it matter: 32 or 64 bits? I think the system on my laptop is 64 bits.

Does it matter: 32 or 64 bits?

For installing extensions it doesn't matter.

Also see https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

Thank you for the extra information. Sometimes I find it difficult to install addons, but I will try again!

Yes, installation successful! Now I have to figure out how to sort. Bij drag and drop....?

Succeeded! Thanks.