Thank you all for your input, appreciate it. I only do 3-4 transaction per year, if that? So I'm kind of new to it all, the terminology, etc.

But the thing I'm not to sure of is sending my Coinbase BTC to my Electrum account. Coinbase says Send/Receive. I'm both sending and receiving. I would think I'm sending to my Electrum account. But I don't want to assume anything? Seems like/is a dumb question, lol? But I'm sending to my Electrum account correct? Rather be dumb here then lose $400+ BTC?

Or I could send directly to the companies BTC address I'm purchasing from?

My next question is I don't see a place to put the companies BTC address too? Just Mobile, email or address? A place for a optional message and pay with BTC.