In the text fields in the activity log you can write notes about the customer and the activity.

On top of formatting the text, you can also embed a video from e.g. Youtube and edit different actions.

Bi clicking on the clock you can change the deadline for the activity (see also the date panel a bit further down on the page):

If the activity was a call, you can click on the phone and register whether the call was successfull or missed:

In the same way you can change the action directly from the log field (you can also do this under customer information to the right):

Regarding deadline of an activity you can instead of clicking on the clock use the date panel. Here you can postpone your activity with 1, 2, 3 or 6 days, 1 or 2 week, or 1 or 6 months - on every button you can see how many activities you already have with the same deadline, so you can plan and make sure not to postpone too many activitites to the same date:

In the top right corner you can add the activity as a favorite, subscribe to it (get a notification if anything is changed), as you know it from other entities in webCRM, and under "Save" you can either save/update or complete the activity (close it):