Touch

When you mean ‘have an effect on’, use affect (NOT touch): ‘How will these new taxes affect people on low incomes?’ ‘Farms in the south of the country have been seriously affected by the drought.’
Get in touch with = communication with (someone) by letter or telephone: ‘Don’t wait until Christmas before you get in touch.’ ‘Mrs Tylor wants you to get in touch with her.’
Come into contact with = meet: ‘In my profession, I come into contact with a lot of teachers.’