I have raspberry pi3 and i want a small help
i dont know how to make the raspberrypi read my rfid tags and show a message on my blynk says “the tag is here” while the rfid tag is on the reader
and while the reader isnt reading my tag shows the message " the tag is lost "
Welcome.
Don’t forget about Googling for projects using RFID tags and RPi… Blynk can help with the data display after you have ID information, but you need a program running on the RPi and proper device wiring for the main RFID part… but none of that will be Blynk specific.
We can help along the way as you learn about Blynk… but the rest of the programming and design is up to you 
Start here and work your way through the Help Files, Examples and Documentation.