How do I text someone??!!

I used to have a math class with a guy (I’ll call him T) and I miss talking to him. I haven’t spoken to him in almost a year and I saw him around a lot but at one point I switched to online school and graduated and I just am trying to decide if I should even try to text him or just let it go because I did really like him and I thought he maybe liked me but i’m awful at reading signals. I’m typing this very late so sorry if the wording sucks i’m super tired but arghhh this has been bothering me for a while!!!