For Android Devices:
Android offers a flexible and user-friendly way to set sounds as free ringtones. Follow these step-by-step instructions:
Choose or Create Your Sound
Before you can set a sound as your ringtone, you'll need to decide what you want to use. You can either select a sound from your device's storage or create a custom sound using a ringtone maker app.
Access Sound Settings
Open the "Settings" app on your Android device.
Scroll down and select "Sound" or "Sound & vibration."
Set Your Ringtone
In the "Sound" or "Sound & vibration" section, locate and tap on "Phone ringtone" or "Ringtone."
You'll be presented with a list of available ringtones. Scroll to the bottom of the list and tap "Add ringtone" or a similar option.
Select Your Sound
A file browser will open, allowing you to browse your device's storage for the sound you want to set as your ringtone.
Locate and tap the sound file you wish to use. It will be added to your list of available ringtones.
Save Your Selection
After selecting the sound, tap "Save" or "OK" to set it as your default ringtone.
Your chosen sound is now your new ringtone for incoming calls
That's how to Set sound as free tonos de llamada that you can refer to here