Visit a reputable website that offers free iPhone tonos para celular. Some popular websites include Zedge, Mobile9, or ToneTweet. Ensure that the website supports iPhone-compatible ringtone formats like M4R.

Use the search bar or browse through the available categories to find the desired ringtone.

Click on the ringtone you want to download. On the download page, select the iPhone-compatible format (M4R) if given the option.

Download the ringtone to your computer. If the website offers direct download to iPhone, you can choose that option to download the ringtone directly on your device.

If you downloaded the ringtone to your computer, connect your iPhone to the computer using a USB cable. Open iTunes and select your iPhone. Go to the "Tones" section and drag the downloaded M4R ringtone file into the iTunes window.

Sync your iPhone with iTunes to transfer the ringtone to your device. Alternatively, if you downloaded the ringtone directly on your iPhone, it should already be available for use.

On your iPhone, go to the "Settings" app, select "Sounds & Haptics," and choose "Ringtone." Locate your newly added ringtone in the list of available ringtones and set it as your default ringtone or assign it to specific contacts.