Searching this forum will give you much more relevant information as opposed to just googling.
However, there are critical differences between the widgets available in the Android and iOS versions of Blynk, especially in the area of location services, so my comment about phone OS (which you didn’t address) arte important.
You’ve previously mentioned an RPi, is this your primary hardware, and if so what language are you trying to program it in?
All of this “big picture” stuff is important when forum users what to point you in the right direction (no pun intended!) as that direction will vary based on OS, Hardware, and what it is that you ultimately want to achieve.
If you just want your wife/girlfriend/significant other to know where your phone is then there are far simpler ways to achieve this rather than with Blynk. If you own an iOS device then this functionality is built-in via Find Friends, and I assume that similar functionality is available in Android.
If you want to use Blynk to open your garage door, make you a cuppa, get your favourite slippers warm and light your pipe for you as you arrive home then the solution will be different again.
The more info you share the more likely you are to obtain useful information and guidance.