Difference between exercise recording methods

[CALM18]

My Mum has recently started a new business as a dog walker. She wants something that tracks her walks and locations, steps and clearly displays the time. She is definitely not tech-savvy at all so needs something to be really simple and easy to use. Her eye sight isn't great so will need to be bold and clear visuals too. 

Water or splash proof would also be a bonus for the nature of her job. 

Does anyone have any suggestions for her? With the maps and GPS functions, can someone explain to me the difference between the phone and the device tracking, please? Is she able to share the walks she has done and look back on them at future dates and is this automatic or does it need to be turned on? 

Sorry for the rambling post and multiple questions and thank you so much in advance!

Moderator edit: updated subject for clarity

[AlvaroFitbit]

@CALM18 Welcome! It's good that the community is growing! 

Thank you for your inquiry. Your mom can try using one of the newer Fitbit devices that has a bigger screen like the Versa 2 or the Charge 3. You can compare devices here. You can use the device to simply track your activities or use it in conjunction with your phone to track GPS data. This is called Connected GPS. Finally you can simply use the app to track GPS activities which is called MobileRun.

Let me know how it goes.

[CALM18]

Thank you!! So how does it work with GPS tracking via a mobile phone? Does
it show a map on the phone app and does it update when you sync or is it
constant?