What's The Diefference Between Private And Sovereign Coins?

Sovereign usually means they are issued by a governement (with the guarantee of face value by that government) whereas private means they were struck by a business.

I will let someone else comment on investment value and chance for appreciation.

Welcome to CCF. I do not consider silver or gold as an investment though they have gradually gone up over the years, their spot prices can slam down and stay down for a while. Once in a while they sky rocket up for a brief period. Silver spot prices are known to be manipulated by some of the major bank traders. JP Morgan was recently fined millions of dollars for it. For me silver and gold are protection against inflation, protection against a fiat dollar. It's real money IMO.

You'll get different opinions if it's best to buy sovereign government minted or generic private mint silver/gold. I think a lot of people have some of both. The best strategy is to buy when the dealers have sales. Compare prices between the dealers. Watch for sales and buy the lowest premiums you can. To avoid fakes buy mostly from well known dealers who have been in business for a long time or from your local coin store. Some of the dealers I like are SD Bullion, Liberty Coin, Hero Bullion, Bullion Exchanges, APMEX, etc. A few online dealers like JM Bullion show their "buy back" prices, what they will pay if you want to sell.

There are some good and not so good YouTube channels you can watch and learn. Two of my favorite channels are Silver Seeker and Yankee Stacking. They discuss prices, differences between sovereign and generic, buying bars or rounds, ways to test silver, avoid fakes, etc.