Transitioning to bottles of formula from breastfeeding

Claire • Proud mummy to baby Girl ❤️
Hi everyone hope you're all well and your babies are happy and healthy. I've been exclusively breatfeeding and plan to until six months. I am going back to work for one week in July when she will be seven months old. Do you think I should give formula for that week or store up enough pumped breastmilk to last those five days ? When I return to work in September my baby will be eight months and on solid food as well as formula milk during the day when I'm at work. Also has anyone got tips on introducing a bottle as she has only drank from breast so far. Any tips appriceated thanks xx