I believe you must still transfer the bitcoins from Paxful to your wallet. Entering information in the receiving wallet is not enough. Only the wallet containing the bitcoins can send the bitcoins.
1. Go to the receiving tab in Electrum and obtain a receive address. The one you generated earlier is sufficient.
2. Go to your account on Paxful.
3. Find the send feature. It will ask for an address and an amount.
4. Copy the receive address from Electrum into Paxful and enter an amount (all I assume)
5. Send.
6.If all goes well, Paxful will debit your account and send the amount to your wallet. After a while, electrum will acknowledge that it is receiving bitcoins and it will let you know when the transaction is "confirmed".