Most Android devices have Dual SIM feature which allows you to use two phone numbers on a single phone. And if you have two SIMs in one device then you wish to use two whatsapp same time. Some phone calls this: 

Parallel apps

and some says:

Dual apps

So you need to find these keywords in your device settings:

#Parallel_apps

#DualApps

And here is how you find what different companies allows you:

1. Hauwai and Honor Devices:

“App Twin”

Open Settings >  App Twin 

2. Asus Phone:

“Twin Apps”

Open Settings > Twin Apps 

3. Vivo: 

“App Clone”

Open Settings > App Clone

4. Oppo device:

“Clone Apps”

Open Settings > Clone Apps 

5. Xiaomi device (MIUI)

“Dual Apps”

Open Settings > Dual Apps 

6. Samsung device:

“Dual Messenger”

Open Settings > Dual Messenger

7. One Plus device:

“Parallel Apps”
Open Settings > Utilities > Parallel Apps

Here is, how to use Dual Whatsapp Feature in your devive:

1. Open settings then go to Dual Apps/Parallel Apps 

2. Select an app that you wish to clone (here you can select Whatsapp)

3. Wait for the processing

4. Now go to the screen and locate second Whatsapp

5. Add your phone number and there you go.

Note: If you don’t find these options in your settings, then you need to go to the playstore where you need to find apps like: Parallel space, Parallel apps, Dual App Wizard and more. You need to install them in your phone to run the same feature as built in devices do.