What must my Oman work contract say and what should I not sign?

Read the contract before signing. It should state your job title, your monthly wage in OMR, your working hours, the contract length, and who pays your return ticket. Do not sign a blank page or a contract you cannot read, and do not sign if the pay is lower than promised. Your job must match your visa. In Oman the employment contract is registered with the Ministry of Labour. Keep your signed copy. Under the 2023 Labour Law your wage must be paid into a local bank account, so make sure the contract reflects a proper salary. If the employer later hands you a different, worse contract, that is a warning sign and useful evidence in any dispute.