Don't underestimate the power of a firm decision. You're not going to quit smoking as a trial run, or as a temporary solution to see if it's okay. You have to quit forever. You will never touch it again. That's the decision. And that's what you want.
It's fine to get help with this. I'm not sure an app is as good as an addiction-recovery group. Many churches sponsor these groups. Don't be too embarrassed to go to a group.
The first few months without are hard. You will hurt. You will hate life. You need countermeasures in place. You need substitutes that are not addictive in any way. These things were recommended by the people I know who quit: drink grapefruit juice, chew on a toothbrush throughout the day, carry some baoding balls. I'm sure there's other foods/drinks that go terrible with cigarettes, I just don't know what they are.
Ultimately you still need will power.
The only way to give up smoking that I have seen is to change to vaping.
Yes vaping! that now evil alternative promoted by the tobacco industry as worse than smoking.
The problem with vaping is that there is no way to gradually reduce the nicotine content over the period of time until you are nicotine free.
All vaping juices are sold in predetermined nicotine levels. 0% 3%, 5% 10% 18%. 3% nicotine is very strong and I do not see anyway to move to 0% from 3% with ease.
Vape juices, like the reduction prescriptions used with heroin users, needs to be more incremental so peopole can reach the desired 0% nicotine levels and be free of nicotine.
nicotine content in store bought juices needs to be 0%, 0.5%, 1%, 1.5% and so on.
people who make their own vape juices are more successful at giving up smoking and vaping because they can change the percentage of nicotine to suit their needs.
It was before smart phones and apps were a thing.
The thing that worked for me was: I stopped putting cigarettes between my lips and then lighting them.