Start by connecting your Trezor device and visiting wallet.trezor.io. Click on the name of your device.
For Bitcoin, Bitcoin Cash, Dash, Dogecoin, Litecoin, and Zcash wallets
Select the relevant account, and and navigate to the Basic tab
Click on Show XPUBs
See here for more details on Trezor xPub.
For all other coins
Select the relevant coin, and view wallet addresses underneath Transactions