Support for multiple accounts made a cameo appearance in the Instagram Android beta app back in November 2015 for some users, but didn't stick around. Now the feature is slowly rolling out to all users of the official app on Android and iOS, so you can easily manage your personal and professional Instagram accounts from the same device. Here's how:
Note: This is a server-side feature that is still rolling out to users.
Step 1: Head to your profile in the app to access the Settings menu in the top right corner.
Step 2: Scroll down to the very bottom of the menu to reveal the Add account option. Tap and enter your details to log in to another Instagram account.
Step 3: You can switch between accounts by tapping your username at the top of the app. Another account (up to five total) can be added through the username menu, as well.
As for push notifications, they will work for all accounts that have them enabled, according to Instagram.
Should you need to log out of any account you've added to the app, simply pick it from the username menu, then head to the Settings area through your profile. There be a log-out option for the current account near the bottom of the list.