There is an exercise option vs selling them. The reason to not exercise is you will have to have enough money in the account to buy them (assuming there has been a big run up). The downside there is in my case I would be re- buying at nearly a 100% markup since i originally bought in. I have 700 shares plus the 15 options.
Remember options are fractional shares, so to exercise you are buying the whole share. Now, you may be able to exercise and immediately sell, I am like you and am just learning.
With TD, you have to be approved to trade options, and im not sure of the criteria. Could be account history or balance or it may just be ceremonial that they require "approval". My TD account is a rollover IRA, so i have not added to it since the rollover 10 years ago. I have just used it to be more aggressive (all of my other portfolio is indexed with Vanguard).
In my case, i will likely sell the options, then re-buy unless i get educated enough to exercise and sell in one transaction. I am going to call them and go through my options, no pun intended.