How to find the best journal to submit a paper to (when having written the title, abstact and full text)?
You need to know your field.  Part of knowing your field is reading lots of papers.  This should give you an idea of what kinds of papers each of the major journals publishes, and what journal may be best suited to you.  If you're a good researchers, you ought to already know what are the main journals that publish research in your area.  If you don't already know that, then maybe you need to spend more time reading published work first.

In particular, the best way to figure out if a particular journal is a good fit for your paper is to read a bunch of papers published at that journal.  That will give you a pretty good sense.  You can use the "call for papers" as a further sanity check, but nothing substitutes for reading what else they have published.

There is no shortcut.  If you are a knowledgeable about your field, a random webpage is not going to know your field better than you do.  If you are not knowledgeable about your field, then the first thing you need to do is to fix that.