People's lives

Technology is very useful for people's life.

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Here the influence of Bahasa Indonesia, and of Indonesian culture, is strong.

1. People

Your reader always assumes that you're making statements about people - NOT aliens, animals or robots - unless otherwise stated:

Chocolate is delicious.
(chocolate eaten by people!)
Driving too fast is dangerous.
(dangerous for people!)
Urbanisation causes many problems.
(problems for people!)

2. People's lives

In our opening example there is a grammatical error - people's life. People is plural and life is singular - so it doesn't make sense to put those words together!

And again, it is always assumed you are talking about people (NOT aliens, etc) and the things that they experience while they are alive (NOT after they are dead), unless otherwise stated.

Chocolate is delicious.
(at any stage of life, as long as you're alive and not dead!)
Driving too fast is dangerous.
(at any stage of life, as long as you're alive and not dead!)
Urbanisation causes many problems.
(at any stage of life, as long as you're alive and not dead!)

3. When people - and their lives - DO matter

If you want to talk about dead people, or about animals, aliens and robots, then the following are possible:

Chocolate is delicious unless you're dead.
I don't know why anyone would want to write this, but if you're not alive then obviously you cannot enjoy chocolate!
Driving too fast is dangerous for animals living in forests that have roads passing through them.
It's a problem for animals, not people.
Urbanisation causes many problems for aliens trying to land their spaceships.
Again, I cannot imagine anybody needing to write this, but these are problems for aliens, not people.

4. Similar problem words

Students experience a similar problem with the word human(s). Again, you only need to mention humans if you're contrasting them with other species or with aliens or robots!