If so, what’s the best software to do it on a Mac?
Probably not, but the software I use is MacDvdRipper Pro.
Check the Digital Millennium Copyright Act of 1998. Basically, it’s not legal to defeat security measures put in place to prevent copying. If the DVD you want to rip has these in place, regardless of if you were planning to do otherwise legal activities (such as creating a backup), you can’t defeat those protections.
There are numerous exemptions and exceptions to the basic rule, however. And it’s a matter of ongoing legal battles.
In the United States you DO have the right to copy a DVD for your own personal use and as a backup.
The problem is you do NOT have the right to circumvent any copyright protection that may be on the DVD.
So there you have it a catch-22. If you’re talking about a regular DVD as opposed to a blu ray, a tool called DVD Decrypter is helpful. Since it’s not legal everywhere I won’t tell you how to find it, but Google is your friend 
Blu Ray is another story all together since it uses different digital rights management (DRM).
Note, as stated, what I said applies to the USA, different countries have different laws which may make DVD copy legal or not depending on the country.
Once you get the DVD files off the disk you need a tool such as Handbrake (free) to convert it to various formats. Other paid programs are easier to use, but Handbrake will do it all and is free and not that hard to use.