Custom keywords are unique words that can be used instead of campaign IDs in your Text-to-Give campaigns.
So instead of advertising your campaign saying
Text 3723 to 1 855 5757888 to support us
You can advertise the following
Text DONATE to 801801 to support us
Which is more elegant and easier to communicate to your supporters.
The custom keyword feature is available to those on the Short Code Plan.
Each organization can have up to one custom keyword and associate it with one of their campaigns.