Hello Zaman,
It’s all good here, busy as always 
How are you?
The VPN label solves the same issue as with “regular” MPLS VPN:
The VPN label helps the PE router to figure out to which RT/VRF the packet belongs.
This is the IPv4-mapped IPv6 address. You can read more about it in RFC 4291 under section 2.5.5.2.
The first 80 bits are zeroes, then 16 bits ones (FFFF in hexadecimal). The remaining 32 bits are for the IPv4 address. This is how we show embedded IPv6 in IPv6 addresses or when we want to present an IPv4 address in IPv6 format.
Hope this helps!
Rene