My phone can't turn on, and when I plug it to charge it shows charging

@kingsleych86979 since it does indicate that it is charging, I would focus on the battery. It is possible that this is an issue with the charging board or the flex cable but then it should not indicate that it is charging. For now, replace the battery.

Since iFixit does not yet have a guide for this, use the one from here It is written in French but hopefully you are using a web browser that can translate it for you.

Replacement batteries are readily available at many online stores.

Now, it is possible that this is an issue with the charging IC obn your main board. For that you would need the schematic and the board layout files so you could do a board level repair, Just remember that a repair like this would require some good tools, excellent skills and experience. So you may have to look for someone around your area that can do it. For now, replace the battery.