Approach 1
A proper way to solve this is image recognition. So you search for the OK button as image. You can do that with the Click Image activity.
But in case you are using the process with another language you might have some issues.
Update: You said you need the text. So you could try the UiPath Connect Browser Get PopUp Text. Note that this only works on Chrome.
Approach 2
Anil_G
Shakib
ashokkarale
sharu_priya
sven.wullum1
Babjee.Vangipurapu
Prathamesh_Trimurti_Hulav
riley
sharazkm32
A_Learner