How to use Segwitaddress.ORG ?

[taera249]

Friends,
I've seen that being non-user of SegWit, there are no such benefits or advantages that we can accrue.
So, I wish to learn how to switch to SegWit completely?

I became aware of Segwitaddress.org to create an address directly from there, but if I use that address, will I be able to sign messages through that address (as the address is being provided with the private key itself)?

I also used an option that asks for a "WIF Private Key" (I entered my Legacy address, i.e.; 19RidcN96xgXkWi8gDwxcmbjjdjfrxpxvv's privkey) there and got an address that could be used to receive funds. But what I don't get here is, where will I see those funds and where can I use them from?
I mean, if I use the same privkey in any wallet, it will still show 19RidcN96xgXkWi8gDwxcmbjjdjfrxpxvv as my address and not the one I get from segwitaddress.org, what should be done here? As well, should I keep me Legacy address' privkey even if I adopt SegWit completely?