Re: bc1 can only receive from another Electrum?

See here.

I read this weeks ago but I still don't get this part.

"receive from most other wallets and websites simply because they consider bech32 addresses as invalid."

If the wallet uses segwit-in-p2sh/P2SH-P2WPKH, they can understand bech32 address as valid?

This means that if you want to receive BTC to SegWit bech32 address you may have problem because some sites/wallets simply do not recognize that type of address.We hope that this will change with time,and in the meantime you can use segwit-in-p2sh address format in Electrum if you follow these instruction : Create SegWit BIP49 Wallet

For security reasons use iancoleman tool offline and on 100% clean PC to keep your seed safe.

Yeah, but I want to know if the wallet uses segwit-in-p2sh they can send to bc1 too.

For example, trezor and ledger uses address starting with 3(segwit-in-p2sh), they can send bitcoins to bc1 address?

Understand?

There is no such guarantee. Support for bc1 is a separate implementation than support for p2sh addresses. p2sh addresses have been around for a long time so everyone supports them.

And yes you can send to anyone from your electrum wallet regardless of the type of your wallet.