For archiving DVDs, we recommend converting them to an ISO file. ISO will make an exact copy of your DVD, including the menus and subtitles. It will also be the same quality as your DVD. The downside to ISO is that the file size is very large.
For the best possible quality, rip your DVDs to MPEG-2 format. The quality is slightly better than with ISO because you lose all the DVD extras and only get the movie. The file size is also quite large with MPEG-2.
To reduce the file size of your DVD collection, try H.265 MP4. This is a great choice because it has very little quality loss and supports 4K and 8K video. The downsides to H.265 are that it requires a lot of computer power during compression, and it is not as common as H.264.
Finally, H.264 will give you a smaller file size (though not as small as H.265), and offers high-quality playback (though not as high-quality as ISO and MPEG-2). It is widely supported by most devices, including mobiles. It is probably the best choice all around for the easiest DVD playback.