Or, in other words, what a Beta Reader should look out for.
Apart from the general grammar (not grammar police level but acceptable, consumable level of grammar) and typos, there are a few points regarding which you can ask for feedback from your Beta Reader.
1. Do the characters feel natural or flat?
A problem many new writers may face is fleshing out the characters. Sometimes, they don't have enough depth to allow the reader to hook onto them and relate to them.
2. Were there any points in the story/chapter you were confused about?
As the writer, we have a lot more knowledge and background information that the readers are not privy to. As a result, sometimes, when a scene feels perfect to us may be very confusing for the reader.
3. Is the dialogue clunky? Does it flow?
Again, another thing many writers struggle with is making the dialogue sound realistic. Sometimes the character's speech comes out very stiff and awkward, and it can ruin the reader's mood. (I've personally come across stories that I had stopped reading because the dialogue is so stiff.)
4. Is the pacing too slow or too fast?
It's hard to get a feel for the pacing of a story without another perspective. And sometimes, the pacing makes all the difference in how invested the reader is in your story.
5. Am I telling the story or showing it?
This happens quite a lot, especially to new writers, where we end up giving a bunch of information to the reader instead of storytelling (in other words, info-dumping). This can ruin the story and bore the readers easily.
These are only a few points; however, apart from that, depending on your story and its' plot, focus, etc., you can ask your Beta Reader to focus on specific aspects. For example, if you're portraying Islam correctly, portraying a certain culture correctly, especially if it is not your culture, etc.