Please, my employer is always asking me to falsify invoices against my will, and I feel guilty about this. Please should I quit the job because of this? Please, I need your assistance.
The simple answer is that Christians are not allowed to lie. It doesn't matter what your employer wants. Your boss has a boss he must answer to. "And masters, do the same things to them, and give up threatening, knowing that both their Master and yours is in heaven, and there is no partiality with Him" (Ephesians 6:9). Since you are being asked to do something illegal, you are best off quitting and finding an honest employer.