Hi welcome to the forum. There’s a lot of info here and I hope you find it useful.
It sounds like this all may be very new to you and your cardiologist should be explaining these results to you, but in the meanwhile I will give a "preview" of what they are likely to explain and I hope it will be helpful. Not sure what led to the echo or what “heart” experience you have, but better "too basic" than no response at all I figure.
So - in this echo, they looked at all four of your heart valves and analyzed their flow and function.
Thin and mobile leaflets with normal annulus and sub valvular apparatus. There is mild mitral regurgitation. TRANSLATION: You have mild backflow on your valve, that's what regurgitation means. The valve is not closing 100% and there's leakage, but it's mild which is good news. Thin and mobile leaflets I am going to assume are good too. In my experience "thickened and stiff" are bad. Though I suppose they could be overly thin or mobile? I'm never had that language in my echos so not 100% sure.
The aortic valve is trileaflet and functionally normal.There is mild thickening and calcification on right and left cusps ,with mild aortic regurgitation. No aortic stenosis. (TRANSLATION: Trileaflet is normal, vs bicuspid two leaflets, which is a common problem many people on this board have. You have mild thickening and calcification of this valve meaning two of the leaflets are slightly crudded up. You have mild regurgitation / backleak again. Again, mild is good news. You don't have any stenosis which is great. Stenosis is when the valve is too narrow and blood doesn't flow through it like it should.
The tricuspid valve has thin and mobile leaflets. The pulmonary pressure is normal.There is mild tricuspid regurgitation. TRANSLATION: Looking pretty good here too. We like terms like "normal" and "mild."
Thin and mobile pulmonary valve leaflets.There is trivial pulmonary regurgitation. TRANSLATION: We like "trivial" even more than we like "mild."
So overall - what I think this means is they might put you on a schedule of echos to monitor this over time and make sure that the regurgitation does not worsen, but the current condition of your valves doesn't seem like it'd trigger surgery, and if you're having troublesome symptoms they might keep looking elsewhere for the cause.
For perspective I have had moderate to moderate/severe mitral stenosis AND /OR regurgitation for 20 years now, and the only way this affects my life is getting an echo once a year. It IS important to follow up with their recommendations for testing because if you have severe regurgitation or stenosis, it can cause enlargement of your heart even though you feel fine.
I hope this helps and is what you were looking for but if not, ask away! Overall though I don't think you should lose any sleep over this while you're waiting for your cardiologist's interpretation. Normal, mild, and trivial are some wonderful words to have in your report.