No. You can’t use the same WhatsApp account on different devices (following the legit way.) So, it is always safe to use your WhatsApp account on the same device. WhatsApp also warns that repeated switching of the devices may also result in a blocked WhatsApp account. So, do not take a risk by repeatedly switching your WhatsApp account on multiple devices. However, it is not a problem to switch your WhatsApp device when you bought a new one.
if u are referrring to android u can download whatschat app from the playstore. but u need to scan qr code same as web.whatsapp.com its a legit way ur whatsapp isnt blocked im using this same since 1year