Odoo's meeting scheduler offers quite a few different options that assist you in customizing a meeting. One of the first things to notice is that, by default, Odoo schedules a meeting for the full day. If your meeting does not have a specific time, you can check the All Day option. After you have checked the option, the Duration field disappears and is replaced with an Ending at field to specify the ending day for the event:
This allows you to specify events that span several days.