Your journi is accessible for all your friends who you invited via link on their smartphone, tablet and computer. Therefore they need to be signed up.
Switch your journi in the “trip settings” to „public mode“. Open the web browser, navigate to your journi, copy the link of the trip and send it to your friends. (e.g. https://www.journiapp.com/j/maxis-trip-to-peru) - Do NOT copy the link for “sharing” the journi on the right next to the headline!
Be aware that your trip is now public and potentially visible for everyone.