Before you being:
Content authors can share any type of learning items only to the groups on which they are the admin of.
Step-by-step process -
Click on Visibility and Access button on the top right-hand side of the editor.
This will open a new 'Visibility and Access' modal.
Click inside 'Add a person, group, or portal' field. Upon clicking you'll get to see the list of groups on which you are an admin.
Select one or many groups that are listed. Alternatively, you can also start writing the group name in this field and you'll get to see the name of the group getting filtered from the list.
You can also remove these groups from the search field by clicking on the (X) button in front of the group name.
By default, content gets shared with 'Can View' permission. When the learning item gets shared with 'Can View' permission a learner has to go through all steps to enroll in the learning.
A content author can change the 'Can View' permission setting to 'Can Enroll'; where a learner from the selected portal will directly enroll in the learning without following any steps.
Click on the 'Add' button to share the LO with the selected group.
After the content gets shared with the group; that group will get listed in the current access section of the 'Visibility and Access' modal with the selected permissions in front of the group name.
You can also change the sharing permissions from Can View to Can Share and vice versa when these groups are added to current access.
To unshare a learning item from the user; click on the (X) button in front of the user name.