Use a scheduled messaging feature in your app if available
On iPhone, use the Shortcuts app to automate sending at a later time
On Android, use Google Messages scheduled send if supported
Use a third-party scheduling app that supports text reminders or delayed sending
Draft the message now and set a reminder to send it later
Save the recipient and message in your notes app for quick copy and send later
Use email-to-text scheduling services if your carrier supports them
Set a calendar event or alarm to prompt you to send the text later