Numbers get underline and go blue

How do you shut off or stop numbers from getting underline. I work at a hotel so i text room numbers a lot they always get underline like its a phone number, Tonight i needed to type a zip code it kept underlining it and created error to where i was sending and asked to send again, on my end i touch blue underline zip code and it ask do you want to call. How do you stop random numbers from texting as a phone number on iphone 7? Thank you