Is the flat rate fee 0.2mBTC or 2mBTC, mBTC meaning milliBTC or one thousandth (1/1000) BTC - as if Bitcoin and cryptocurrency generally were not complicated enough.
If you want to know more about bitcoin transaction fee, you can read these:
Beginner's Guide to Transaction FeesBitcoin Transaction Fees - Everything in oneMinimizing bitcoin transaction feeFor mempool, you can use these sites:
For beginners:
https://mempool.space/For advanced users:
https://jochen-hoenicke.de/queue/#BTC,24h,weightIf I will brief it, the fee is in transaction weight or virtual size/byte (vsize/vbyte) multiply by the feerate in vbyte which you can check using mempool.
Fee= feerate (in sat/vbyte) * vbyte
Are there any other additional fee?
No. Fee are taken by miners to include your transaction into a block, in the process, your transaction will be confirmed and successful.
Additional fee can be taken by TrustedCoin if you are using Electrum 2FA wallet just as hosseinimr93 and khaled0111 commented.
Exchange charges exorbitantly far higher than the actual bitcoin transaction fee
But the fee are not actually bitcoin transaction fee, they are charged by third parties (TrustedCoin and exchanges)
Does any Electrum fee apply to all transactions (i.e. receiving and sending Bitcoins)?
No, it applies only to senders, not receivers.
But it would be interesting for you to read about child-pay-for-parent which receivers can do if the sender uses low transaction fee, especially when the mempool is congested but the receiver wants the transaction to get confirmed early, the receiver can create another transaction, spending part of the unconfirmed UTXO using higher fee that is able to make miners to include two of the transactions into a block and get confirmed.
Any other thing I need to know about Electrum mobile wallet?
Just as khaled0111 commented, desktop Electrum has more features than Electrum mobile wallet, like the use of Console, testnet and coin control (able to manually select inputs), but on mobile, you can still take advantage of address freeze, but using coin control is more flexible as you can still freeze certain inputs manually on the same address. You can also only use desktop Electrum to verify messaged signed with bitcoin address and also for public key encryption message. In short, there are many features even not yet mention that is on desktop Electrum but not on mobile Electrum.
Thanks for your reply. Briefly, how do I verify Electrum mobile (Android) wallet signature specifically; and what is "BIP39 seed phrase"?
@DireWolfM14, thanks for your reply, I did not pm back again because I know you will read my reply here. I hope Bitfellow will be able to follow you posts into details.
@Bitfellow, seed phrase generates the seed, the seed generates the master private key and master public keys, from master private keys, the child keys (child private keys and child public keys) are geerated, from the child keys, the addresses are generated. Simple sentences can not perfectly explain this, you can read more about it on the GitHub mastering bitcoin link below.
https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch05.asciidoc