You will need the Full SMS permission to perform these actions.
You will also need the Contributions Settings permission to perform these actions.
First you will need to set a Keyword for the designation, then you will need the steps on how to set up the text message contents.
How To Set a Keyword for a Designation
Contributions > Settings > Select Edit from the dropdown at the end of the designation you are trying to edit
Under the Options section of the pop up locate Text Giving > Select Add Text Giving Keyword
Here you can Create a Keyword for this designation
**Be sure to Save your changes.
How to "Text to Give" a donation to a specific designation
"Text to GIVE" donations can be specific to a designation. After you have created a Keyword under the designation as described above, your donors can now Add the Keyword after the word GIVE and the amount they intend on donating.
GIVE + AMOUNT OF DONATION ($25) + KEYWORD (TEST)
Example of a SMS a donor would send: GIVE 25 TEST