Eating raw shrimp is not recommended because of the risk of food poisoning, so you have to make sure it’s cooked thoroughly. Good thing you asked.

Here’s a full detailed guide: https://www.yummly.com/dish/329296/how-to-tell-when-fish-and-shrimp-are-perfectly-cooked (this also has some tips on how to cook it through boiling so read that)

You can tell the doneness by the internal temperature (120 degrees Fahrenheit) but I doubt you have a food thermometer on you. I think the easier way is to look at its color. Raw shrimp is a translucent gray while cooked shrimp is opaque white with some pink and bright red accents – so check for translucent gray parts, if they’re there, cook more.

You can also tell by the shape of your shrimp. Shrimp muscles contract when cooked. Basically, perfectly cooked is in C shape and overcooked looks like an O. I say aim for an O shape, overcooked is better than undercooked in this instance 😀