For cryptocurrencies, Trust Wallet, Atomic Wallet are good secured decentralized wallets. Since you are a newbie to crypto, please stay safe with any crypto wallet, see https://www.blackhatworld.com/seo/wallet-passphrase-private-keys-never-share-it-with-anyone.1365639/#post-14793914.
Regarding selling Bitcoin and receiving into Skrill, not directly possible, because in Skrill, only bank transfers coming from a bank account held in your name are accepted into your Skrill account. A workaround to that is localbitcoins dot com (they have escrow) where you can sell Bitcoin and instruct seller to send money to your bank account and then from your bank account you can transfer to your Skrill account.