Ppf investment under sec 80c clarification required

Hi,

My mother is 72 years old and in the last couple of years her annual income [from various Fixed Deposits] is exceedng the Rs 3 lakh limit set for senior citizens. So to bring down her tax liability, I have asked her to invest in PPF under Section 80C. However, I need a clarification regarding PPF:

Let's say she opens a PPF account this month and deposits Rs 1 lakh in the account for the year 2018-19. This means Rs 1 lakh will be deducted from her total tax liability for 2018-19. But what about the subsequent years? Will the deposits she makes in the PPF account in 2018, 2019, 2020, etc also be considered as deductions under Section 80C for those respective years? 

Thanks!

Debashish