You can Quick Create an Activity from anywhere within Mercury.
Click the Quick Create icon in the Mercury Menu and select Activities.
You will see a list of Activities available to create.
Ensure that the Regarding field is filled in, in order to link the Activity to the record. For example, adding the Regarding on a Candidate Call will ensure the activity is shown on the Candidate's Timeline.
NOTE: the record within the Required field will get an email sent to them informing them of the activity.
Fill in the mandatory fields on the Quick Create form and click Save.