Let me tell you that Whatsapp, backup chat history every day at 4 AM in your phone’s internal storage. So, if you have backup of whatsapp chat history, then you can easily restore chat history from your backups.

Here how to whatsapp data on your Android:

• Simply uninstall WhatsApp on your phone.
• Then re-install WhatsApp on your phone from Play Store.
• Launch WhatsApp and verify your phone number. After verifying your phone number you will be prompted to restore your messages history.
• Simply tap on “Restore” and everything of last 7 days will get restored.

If you do not have any backup, then it is highly recommended that you must use Android Data Recovery Software to restore lost or deleted data from your Android phone.

https://drfone.wondershare.com/whatsapp-tra...-to-iphone.html

Seems like android to iOS also same

This is quite easy, all you have to do is to move the entire WhatsApp folder from Android to Apple phone. But, before you proceed make sore to activate the WhatsApp on the new Apple phone. Once you have installed and activated the Whatsapp on the new phone, you are ready to transfer the Whatsapp installed folder from android to iPhone.
However, you can use the Android data transfer tool to perform the task but still, a simple copy paste will do the job!!