

Salesforce doesn’t allow users to create a report based on an individual multi-picklist field or group the reports based on an individual multi-picklist.
A workaround for this is to create a custom object which holds the multi-picklist values of the object you are trying to build a report on.
Challenges on Multi Select While Reporting in Salesforce
Create a custom object which has a master-detail relationship with your reportable object. Create two fields. One which holds the multi-picklists and the other which holds individual values.
If it is necessary to build reports based on multi-picklists, then follow the below steps as a workaround for the limitation.
Let us consider Account as the object which has multi picklist fields.
Scalable, Doesn’t impact the performance, easy to implement, easy to migrate
None
Using this approach, reports can be created on multi-picklist values.