I am confused about require and import in node.js.
Some modules use require and some use import can we use only one or the other for all modules?
Yes, you can exclusively use import statements to load modules.
You must configure Node to use the ESM loader. The most common method of doing this is setting the "type" field in package.json to "module":
// package.json
{
"type": "module"
}
See Determining the module system in the docs.