Here’s how to set up bulk actions in Salesforce Lightning.
In Salesforce, click the Setup icon and select Setup.
Click the Object Manager tab.
Find and select the Lead label.
Click Search Layouts for Salesforce Classic.
Find the List View layout. Click the drop-down to the right and select Edit.
Under Custom Buttons, find and select Add to Marketo Campaign (lightning) and Send Marketo Email (lightning). Click the Add button.
You will now be able to see bulk action buttons in your Lead List View.
Repeat the same steps to add bulk actions in your Contact list view.