What internet package do you currently have and what are you looking at going to?
If you are on Fibre and have a modem that is compatible with the internet plan you want to upgrade to it can be done in a matter of minutes most of the time. There would be no interruption in your service.
If you are on copper, you may require a technician to upgrade the speed if they would have to bond it. This means bringing in a second line to merge at the modem to combine their speeds and give you the overall plan you jump up to. If bonding is not required you will still see no interruption in service but the order would most likely have to run overnight and your speed would increase the next morning.