Is money earned from a job, obtained after falsifying some grades in the transcript during the application to join the educational institution, halal or haram?

If you are competent in your work and perform it as required, then there is no blame upon you concerning the wage you receive. Your falsification to enter the competition does not affect it. However, the sin of falsification is upon you, and you are obliged to repent from it by seeking forgiveness, showing remorse, and performing good deeds.