To view an account you do not own (i.e do not have private key for) with SubWallet. All you need is an account address.
Step 1: Open SubWallet. Please click on the round item on the upper right corner of the wallet. You would see the Account section as below:
Please select the option "Attach read-only account".
Step 2: Fill in the information and click the button "Add the account with identified address", and you have successfully attached a read-only account!
As the name suggest, this type of account is read-only. You would not be able to transfer funds or actively participate in any activities with this type of account.
SubWallet helps you identify your read-only accounts with the eye symbol as shown below, so even if you are creative when naming this account, you can still identify it. Please make sure that you are not in a read-only account if you want to make transactions.