Your Galaxy J6 Plus has a microSD memory card slot. If your personal computer is compatible with that card type (Most laptops are so-equipped), you should be able to save a music file
The Galaxy J6 Plus is equipped with Bluetooth version 4.2 (with ANT+), which lets you connect to your computer wirelessly. Just pair phone and computer together and drag and drop your music files from your computer to your Samsung Galaxy J6+.
If all of the above methods do not work with your Samsung Galaxy J6+ or if you prefer not to buy new accessories, you can still use one of the numerous free '3G Uploader' services available online. A search on Katapulco should retrieve plenty of them. 3G uploaders are simple: Save your own music on their web site and they will provide a temporary URL. Navigating to that URL with your Samsung Galaxy J6+'s browser should download the free ringtone.
More on free ringtones
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