You can use the Apple Shortcuts app to create a shortcut to speed dial or call a number, and edit the text for it to say whatever you want. It can say "Call, then press 1".
click here ➜ Shortcuts User Guide - Apple Support
Once the shortcut has been created, you can go to the Widgets pane by swiping all the way to the left to bring it up, then scroll to the bottom to find the Edit button. Tap on it, then tap on the (+) at the top left corner and scroll down until you find the Shortcuts app. From there select the shortcut icon, it should show the most recently created one there directly. Otherwise, you can select it, and then tap on Add Widget to add it, and then tap on it again to change which shortcut it should activate. Select the one with the number and text you edited. And it will be added to the widget list and show the text you set for it. You can then drag it onto a home screen and place it wherever you want.
Click here ➜ How to add and edit widgets on your iPhone - Apple Support