Textbooks say 60-100 but some people, and particularly athletes, are often seen to have lower heartrates at rest (mine is is anywhere from 52-61 at rest on average and goes as low as 39-40 while I sleep - I am woefully out of shape but have a somewhat larger than avergae heart fyi and if you can tell me whether thats a good thing or a bad thing then you're more clever than I). The only way I know of to lower resting heartrate is to strengthen your heart through exercise (it improves the efficiency of your muscles including the heart and also increases the stroke volume of the heart so that you pump more blood with every beat) but I don't know how issues like age, heart disease etc affect that process. If your heart rate is high for a medical reason then I'd say you should talk to your doctor about whats best for your cardiac health and not worry so much about a static number like resting heart rate without thinking about it relative to other measures of heart health and your doctors suggestions. Good luck!
I heard normal hr would be 60 to 80 at rest
Avg HR is 60-100. However, it is not uncommon for HR to drop below 60 during sleep/rest.
I do know that HR tends to rise quickly when we are deconditioned. To that end, exercise could be helpful for lowering HR.