I have been at the same company for 10 years and I am pretty happy. This year I decided to ask for a raise.
If you haven't received a raise in 10 years, it is very likely you're being paid below your market rate just based on inflation alone.
I wrote what I thought was a fair letter justifying the raise. I emailed it to my team lead and his boss.
Asking for a raise through email first is sadly just asking to be ignored and dismissed. I personally would still take your request very seriously, but it's just not the norm to see that sort of sensitive request via email.
To ask for raise, you should talk to your direct manager to discuss face-to-face. Don't involve other people from your team like leads or your manager's boss. Your manager may request that you help them put together a list of reasons when you should receive a raise, especially if this is off cycle. Do this promptly (or as @AndreiROM suggested do it before the meeting and bring it with you) to ensure you're not the bottle neck in the process.
Make sure you get an estimated timeline of the process and definitely follow up on how your request is progressing.
This is one of those case if you really want the raise, you need to be the one to drive the whole thing forward. That means following up with your manager on what's going on with your request. I'd recommend interviewing externally to get a gauge of your true market value to help you negotiation internally or as an exit strategy in case things go south.