Green line
Green vertical line appears on display left side automatically what to do
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If that line apperas in all screen pages / apps, it looks like a screen problem.
I suggest that you make an appointment and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> Apple – Location Selector.
After checking it out, they'll give you all the available options.
Regards
Giulio