For receiving private posting key you can use login and password from Steem / Golos accounts. Or you can take it from the Steem / Golos wallets by yourself and save it on mapala.net. For more details about posting key saving see the instruction
Mapala.net servers dont get any keys and passwords. All the transactions occur between you and blockchain. Или All the transactions are between you and blockchain. After that the key becomes encrypted and stored in browser cookies.
How to get a posting key.
You have to copy and save in appropriate posting field your private key from GOLOS platform to publish posts, vote and receive awards. You can find private posting key ongolos.io in “permissions” tab. Please note that private key begin witha a number 5.