Can i list all files using secondary account.

You can "link" or "authorize" an API app to connect multiple accounts. To do so, you should go through the OAuth app authorization flow for each account you want it to connect to. You can find more information on the OAuth app authorization flow in the OAuth guide.

At the end of the flow, your app will receive an access token for that account. When using the Dropbox API, each access token will allow your app to access one account. If you need to access two different accounts, you'll need two access tokens. (One for each account.)

So, if you want to access your company Dropbox account via the API, you'll need to go through the OAuth app authorization flow while signed in to that account.

(One shortcut is that if the app is owned by the account you want to link it to, you can use the "Generate" button on the app's page on the App Console, as noted in the OAuth guide.)