I like the link posted in the comment section (When to use icons vs. icons with text vs. just text links?) but I wanted to specifically address the accessibility aspect since the question was tagged with that.
Accessibility can be thought about in two ways:
"Conformance" is about (voluntarily) adhering to a set of guidelines, which is different from "compliance", which is about adhering to a law. They seem similar but are quite different.
Think of speed limits. If you see a yellow caution sign that the road curves up ahead and the (suggested) speed limit is 35 mph, that's a "recommended" speed limit but is not required. If you don't go 35 mph, you're not breaking a law (compliance). You might run off the road because you're driving too fast for the conditions and that could lead to other legal implications, but not going 35 is not breaking the law. If you do go 35 mph, you are "conforming" the suggestion.
On the other hand, if there's a white regulatory sign saying the speed limit is 35 mph, then not going that speed is non-compliant.
So you "conform" to recommendations (yellow sign) and you "comply" with legal requirements (white sign).
I say all that because accessibility has "guidelines", which are voluntary, and it's recommended you "conform" to them but if you don't, you're not breaking any law. But like running off the road by not following the suggested speed limit of 35 mph (yellow sign) might lead to other legal issues, not following accessibility guidelines could cause other legal issues too.
Now, with all that being said, there are some guidelines for accessibility called the Web Content Accessibility Guidelines (WCAG). It is strongly encouraged to follow them to make websites, native apps, documents, etc as accessible as possible to the greatest number of people. But there is nothing in those guidelines that address the use of icons vs text or a combination. There are guidelines that if you use an icon without text, then the meaning of that icon must be conveyed to assistive technology (such as a screen reader or speech interface)(WCAG 1.1.1 and 4.1.2).
This is all on the "conformance" side of accessibility.
The other way to think about accessibility is from the usability side. You can have a website that follows all the conformance guidelines (WCAG) but still be an unfriendly and hard to use website. That's where your question about icons vs text vs both comes into play. As mentioned, there aren't any official accessibility guidelines on which to use so at this point, you have to do some user testing. The Nielson Norman Group has some info about icons.
Personally, I like to give the option to the user. That is, design your app so that you can have just an icon or just text or both and put it in your settings and let the user choose which they'd prefer.