Yes. Flashing a full firmware will wipe everything (apps, photos, contacts). Back up your data before starting.
For "dead" or stubborn bootloop cases, you may need to use EDL (Emergency Download) Mode by shorting two test points on the motherboard, but this is only recommended for advanced users. Tutorial for Firmware Installation - Vivo vivo v7 flash file repairmymobile full
: The official Android OS image (usually PD1718F ) specific to the Vivo V7. vivo v7 flash file repairmymobile full
— these define partition mapping.