You can learn more about creating Contact Sources for your database here. In this post I just want to cover how you would go about adding or editing the Contact Source for multiple contacts in bulk.
From your Advanced Search page, after running a search that will include your desired contacts, place checks to the left of the names of those contacts for whom you want to edit the Contact Source:
Then, click the Contact Options menu above your search results and select Bulk Actions:
Next, select Change Contact Source from the Bulk Contact Actions modal that appears.
After clicking Change Contact Source, you'll then see the Change Contact Source modal, where you can then clear the Contact Source for each of these records or choose from your existing Contact Sources to apply one of them to these contact records:
The Contact Sources available here are those that your database users have established within your CRM - you can learn more about adding Contact Sources to your database here.
To select a Contact Source, just click inside the Change Contact Source box, click your desired Contact Source and click Change Contact source:
In the above example, once you click Change Contact Source, these contacts will have "Seminar" displayed in the Contact Source field within their records.
As you can probably see, it's a quick and easy method to change the Contact Source for multiple clients at one time. Note: Contact Source is a searchable field within Redtail CRM, so you can easily search for all records with a specific Contact Source.