There can be all kinds of reasons you don't want to send a text message or an email straight away—maybe you know the recipient is busy or in a completely different time zone, or perhaps the information you're sending won't be relevant for a while.
Today's mobile and desktop apps are adapting to give you more options when it comes to scheduling your messages for the future. These are the tools you can use and the options you've got.
The Google Messages app that's the native SMS app on many models of Android phone (and available to download) now has a scheduling feature built in. The trick is to tap and hold the Send button (the arrow icon on the right) once you've composed your message.
This will bring up a panel with some suggested times later in the day. You can select one of these, or choose Pick date and time to specify an exact day and time. Until then it will stay as pending in the app, with the scheduled time and date above it.
If you're using Android, the exact setup of your phone will depend on the make and manufacturer, and you might find you've got other options. The default Messages app on Samsung devices, for example, has a scheduling function built in for delaying the sending of texts.
Tap the + (plus) icon to the left of the text box—or the > (greater than) icon if you can't see the + icon—then choose Schedule message from the pane that pops up. You'll be prompted to pick a date and a time to send the message, then tap Done.
Over on iOS, the default Messages app doesn't include a native scheduling function, but you can use Apple's own Shortcuts app for the job. You then need to install the Delayed Time iMessage shortcut, which you can find by searching for it in Shortcuts, or get there directly from here. If you tap the three dots at the top right corner of the shortcut, you can see how it works and maybe tweak it to suit your own needs.
Run the shortcut with a tap, and you'll be prompted for a contact, a message, and a time and date when you want it to be sent. The shortcut then waits for the specified amount of time before sending your SMS or iMessage. It's best not to schedule messages too far in advance, as this trick needs the Shortcuts app to still be running in the background at the scheduled time you've specified.