macbook 2016 21w charger replaced with 61watt
From: Find the right power adapter and cable for your Mac notebook

Power adapters for Mac notebooks are available in 29W, 30W, 45W, 60W,
61W, 85W, 87W, and 96W varieties. You should use the appropriate
wattage power adapter for your Mac notebook. You can use a compatible
higher wattage power adapter without issue, but it won't make your
computer charge faster or operate differently.

Also:

Make sure you're using the correct USB-C charge cable
For the best charging experience, you should use the USB-C charge
cable that comes with your Mac notebook. If you use a higher wattage
USB-C cable, your Mac will still charge normally. USB-C cables rated
for 29W or 30W will work with any USB-C power adapter, but won't
provide enough power when connected to a power adapter that is more
than 61W, such as the 96W USB-C Power Adapter.