See the Multivalued video.  It explains why they are not recommended how to get rid of them, and alternatives to use.

Thank you very much Scott, I thought that it was possible to build an actual combo box as opposed to a list box, is there such a thing or is it a big no no? I can't seem to find the answer, I appreciate your time so if you can't answer I'll understand. Thank you again:)

Maybe terminology is the issue here.  Are you just wanting to choose an item from a list?
That would be a Relational Combo.

If you need multiple choices to be true then take a look at the Multiple YN
That shows how to be able to choose multiple items in the correct way.

If I'm not understanding correctly, maybe you can give us an example of what you are trying to accomplish so that we can help you better.

As Scott said, multivalue fields are difficult to work with, in queries and in VBA.  Use MVF only if you need a multiple-choice type of combo box with checkboxes (see picture below).  But I would rather find other more manageable ways to do the same thing than using MVF to do it.

Hi Kevin, Hi Scott,
That's exactly what I meant, the MVF. That's because the subform with checkboxes, although a viable option, it is not so good to look at and to work with in the long run, but certainly something it can get you by if you don't know VBA well yet. So I guess the answer is that I will have to wait until I get to use VBA properly to open a dropdown menu with checkboxes? OR does the option not exist at all, better to have multiple distinct fields, that is, different relational combo boxes to select from?
Thank you both for your input!

Hi Elena, Richard has a video on using "fake combo boxes" that offer you more options on their looks and functionalities:

     https://youtu.be/FET8JG8w4Xg

Basically, you use subforms for that.  You turn off their borders, record selectors, etc. to make them look "plain," and make them invisible or visible when necessary.

To add checkboxes to a combo box without using multivalue fields, i the combo box's rowsource needs to have a built-in Yes/No field.  You may need to create a temporary table for that.