bech32 - Native SegWit details

Bech32 (defined in bip173) is an address format proposed for native SegWit outputs, whereas legacy SegWit wraps outputs in a P2SH (Pay to Script Hash - address starts with '3'), called Nested P2SH.
Bitcoin Bech32 addresses start with "bc"

Base58Check is used for encoding Bitcoin addresses.
Base58Check encoding is used for encoding byte arrays in Bitcoin into human-typable strings.
A set of 58 alphanumeric symbols consisting of easily distinguished uppercase and lowercase letters (0OIl are not used)

Bech32 addresses have several advantages over the old Base58 addresses:

• The QR code is smaller,
• The protection against typing error is better
• It enables auto completion
• Due to only consisting of lower cases it should be easier to type and to be understood when read aloud.
• Case-insensitive too.

Nested P2SH (Legacy SegWit) : they take the existing P2SH address – starting with a "3" – and put a SegWit address into it. This enables a high grade of compatibility to existing wallets, as every wallet is familiar with these addresses, but it is some kind of hack, which results in SegWit transactions needing around 10 percent more space. Obviously, this contradicts the goal of increasing capacity.

Other than the Nested P2SH addresses, Bech32 addresses are natively SegWit compatible. This means the transaction does not need extra space to put SegWit in the P2SH address.

Wallets using Native Segwit (Bech32; with benefits of lower transaction size, hence even lower fees):
Electrum - Desktop, Android
Trezor - Hardware (not in gui yet, can be accessed via trezorctl)

Wallets using Legacy SegWit (Nested P2SH)
#Bitcoin Core daemon (not in gui) - Desktop
Electrum - Desktop, Android
Armory - Desktop
Samourai - Android
GreenAddress - IOS, Android, Web
BitGo - IOS, Android, Web
Trezor - Hardware
Ledger - Hardware
http://SegWitAddress.org - Paper