To get one inbox with access to multiple accounts:

1. Set up a third-party email client to combine emails: Email clients like Mozilla Thunderbird and Mailbird allow you to manage multiple accounts in one place. Download the client and add your existing accounts to sync all emails.
2. Set up automatic forwarding to one email address: Configure each email client to forward emails to a single address. This will automatically combine different emails into one inbox.
3. Check out a Gmail plug-in: If you’re a Gmail user, you can add a plug-in to your Gmail account to access and manage multiple email accounts.