How do transactions get included in a block?
Are miners responsible for deciding which transactions are included in a block? I thought miners work towards finding the solution for the block.
Miners maximize their income, so they pick the transactions with the highest fee (per (v)byte).
If so, the block must be already created ? Who created this block ?
Miners create the blocks.
When I send a bitcoin transaction, does it get sent to a miner ? How does my client (such as electrum) know whom to send the transaction to?
The keyword is "mempool". All transactions are shared with all miners, but miners are free to pick them as they please.
What other parameters are taken into consideration while including a transaction into a block for eg. Fee? If so, is it possible that Russian bitcoin addresses can give an incredibly large fee to incentivise miners to include the transaction?
There are no "Russian Bitcoin addresses". Bitcoin doesn't have a nationality. But yes, anyone can pay a higher fee to get miner's priority.
How would the government know that a USA miner would pick up the block which contains a russian address transaction? What if the block is won by someone in Australia? Can Russia mine their own blocks and add to the Bitcoin network?
Many miners are anonymous, and generally miners are quite mobile: if China bans them, they take their hardware and move elsewhere.