1.    If you are sending the offer to one single customer, then you can write the customer email/phone and send offer to that customer.

2.    If you want to send the offer to multiple customers, then create a customer segment and then send offer to that particular set of customers. Do NOT send offer to multiple single customers one after another. When you create a new offer the previous offer of same type gets INACTIVE. In that way you might create a new offer before the previous offer got triggered from server (which usually takes few minutes). Below are the steps to send offer to a set of customers.

2.1.    Create a Customer Segment:

2.2.    Add customers to the Customer Segment:

    2.2.1.    Go the Enrolled Customer listing and find the customer from the list. You can search with email/phone.

    2.2.2.    Click on "Edit" and assign the customer to segments as below. Add all the targeted customers in this segment one by one.

2.3.    Now when you send custom offer, you can select the newly created Customer Segment from the dropdown as below:

This will send the offer to the customers in that particular segment.