How old is the Earth?

The Earth was formed approximately several billion years ago through accretion from the solar nebula.

3.5 billion years ago

Life appeared on Earth at least 3.5 billion years ago during the Precambrian era, after the geological crust began to harden.
Humans have found fossilized microbial mats such as stromatolites in 3.48-billion-year-old sandstone in Western Australia. Other natural evidence of biologically created material includes graphite in 3.7-billion-year-old metamorphic sedimentary rocks in southwestern Greenland and "remnants of life" in 4.1-billion-year-old rocks in Western Australia.
Photosynthetic organisms appeared approximately 3.2–2.4 billion years ago and began releasing oxygen into the atmosphere. Life remained largely small until about 580 million years ago, when complex multicellular life forms emerged, evolving over time and culminating in the Cambrian explosion around 541 million years ago.
It is estimated that over 5 billion species, or 99% of all species that ever existed on Earth, have become extinct. The current number of species is estimated at 10-14 million, of which 1.2 million are documented and over 86% remain undescribed. However, recent estimates suggest that as many as a trillion species live on Earth, with only a fraction of that number described.

Source: https://vtcnews.vn/trai-dat-bao-nhieu-tuoi-ar909245.html