In file included from c:\Users\Dell\OneDrive\Documents\Arduino\libraries\Blynk\src/BlynkApiArduino.h:14,
from c:\Users\Dell\OneDrive\Documents\Arduino\libraries\Blynk\src/BlynkSimpleEsp8266.h:24,
from C:\Users\Dell\OneDrive\Documents\Arduino\projexct\projexct.ino:4:
c:\Users\Dell\OneDrive\Documents\Arduino\libraries\Blynk\src/Blynk/BlynkApi.h:39:6: error: #error "Please specify your BLYNK_TEMPLATE_ID and BLYNK_TEMPLATE_NAME"
39 | #error "Please specify your BLYNK_TEMPLATE_ID and BLYNK_TEMPLATE_NAME"
| ^~~~~
I moved your topic to an appropriate forum category @saurabh11.
In the future, please take some time to pick the forum category that best suits the subject of your topic. There is an "About the _____ category" topic at the top of each category that explains its purpose.