MoneyAM have a tool for this.
With your cursor over your required future position in the posting box, which you have previously chosen as being the pertinent position for your link to be eventually placed, then first click on the

symbol above the box where you type your post.
You might get well now get a message asking for your permission to ".......allow scripted windows...". This message is dependant on your machine's security and pop-up blocker settings.
If so, click on it and 'Temporarily Allow Scripted Windows'.
If you don't get such a message, then ignore the above comments.
Click on the chain link symbol once again.
Up pops a box with a facility to insert a URL address.
Duly insert it, taking care not to doubly insert the 'http://' part of the address.
Click on OK
Insert any text you want to show, such as 'HERE'. Click on OK once again. Or you might like to ignore typing anything at all and just click on OK. In which case the address itself will show instead of 'HERE'.