As a group member, you can leave a group at any time by clicking the three dots in the group and selecting "Leave group." As a moderator, you must transfer the moderator status to at least one other person before leaving. How to do this is explained in the linked article.
As a group member, you can leave a group at any time.
To do this, select the desired group. Click the 3 dots on the right. A menu will open. There you can select “Leave group”.
For the web version:
For the apps:
If you are a moderator of a group, you will be asked to assign the moderator status to at least one other person before leaving the group. Once at least one other person has this status, you as the original moderator can leave the group.
How to transfer the moderator status can be found in this article: How can I give up the moderator status?