Only if the problem is in connecting them to a computer, using standard software provided for them to do so.
If the problem is in using them with a smartphone application then for Android phones or tablets you may be able to ask at Android Enthusiasts or for iOS devices there is Ask Different. For using the webapp there would be Web Applications.
Yes you can ask about using MS Office Word.
To help get answers remember to provide info such as your version, maybe what OS you're using, and what you've attempted so far to help narrow down the focus and relevancy of answers.
To quote the close reasons:
Questions seeking product, service, or learning material recommendations are off-topic because they become outdated quickly and attract opinion-based answers.
So, in a word - no, this won't be on topic.
Only if the problem was in connecting or using it with your computer.
Smartphones would not count as a computer though if your problem is with the Android application talking to it then there would be Android Enthusiasts or for Apple devices you could ask at Ask Different.
As Burgi mentions for the actual hardware itself there may be other sites on the ...
Sadly I don't think these devices fit within SuperUser's scope.
As it is more an IoT device you might want to try Internet of Things. According to their help files
If you have a question about...
controlling, automating and sensing the environment using electronics ('smart devices'),
... you're in the right place!
I would say that a FitBit is a smart ...