Are you on a mobile device? They may not be easily available. I am using a desktop computer and below the answer box, I see, and can click on, all of the letters that have accents. Supposedly you can type them directly if you are by using your keyboard shortcuts but I haven't been able to get that to work on my computer. I may need to add something to my browser to use the shortcuts like CTRL Shift ^ c to get the ĉ.
A very tedious method is to create a document with all of the accented letters in it. Leave it open and copy and paste from it when you need one. If I use an accented letter a lot, such as the ý, I just keep it in my "paste" buffer.
I hope this helps you!