Based on the level of respect or formality, you can say "Please enjoy your meal" in Korean in 3 ways:

• Informal: mat-itge meokeo (맛있게 먹어)
• Formal: mat-itge deuseyo (맛있게 드세요)
• Very Formal: mat-itge deusipsiyo (맛있게 드십시요)

- please: jom(좀), jebal (제발)
- to enjoy: meokda (먹다), jeulgida (즐기다)
- your: neo-eui (너의), dangsin-eui (당신의) - omitted here
- meal: eumsik (음식), siksa (식사)

Please refer to How to pronounce Korean Alphabet for the English pronunciation in this answer.