You can import simple products in Magento 2 by CSV from admin panel.
Log in to admin panel with your credentials.
Go To System -> Data Transfer -> Import
From Entity Type Select Products.
Select Add/Update from Import Behavior settings.
Create CSV file for import only simple products. I have created simple products CSV file, Download Simple-Products-CSV for check possible column and data of the simple product.
There are many columns for import product in Magento 2. Check each column description below in details,
sku => Product Unique SKU
attribute_set_code => Product Attribute Set code(get from Stores -> Product -> Attribute sets)
product_type => simple for import simple product(Possible types simple,configurable,bundle,grouped,downloadable,virtual)
website_id => 1 (Select id from Stores -> All stores -> Website choose your website and get id)
product_websites => base (Select website code from Stores -> All stores -> Website choose your website and get code)
name => Product name (keep unique name so dont face error for URL key)
short_description => Product short description
description => Product long description
categories => Products categories (Keep comma separated for multiple cateory, Give full path from Default Category to your category, Ex. Default Category/Gear/Bags
tax_class_name => Product Tax class name
meta_title => Product meta title for SEO
meta_keywords => Product meta keyword for SEO
meta_description => Product description for SEO
price => Product Original Price
special_price => Product Special price
product_online => 1(Possible value 1 or 2, if 1 enable and 2 for disable product)
color => Product color (Optional attributes)
size => Product Size (Optional attributes)
weight => 1 (if value is 0 product is virtual)
visibility => Not Visible Individually (Possible values Not Visible Individually, or Catalog or Catalog, Search or Search)
qty => Product Qty
is_in_stock => 1 (Product is in stock or out of stock)
base_image => /pic1.jpg (Product main image in product page)
small_image => /pic1.jpg (Product small image in cart page)
thumbnail_image => /pic1.jpg (Product thumbnail image in listing page)
additional_images => /pic1.jpg,/pic2.jpg,/pic3.jpg (Product additional image for product page gallery)
For Image import using CSV, give product name with prefix as /.
Example Product name is pic1.jpg, gives the name for a column is /pic1.jpg
Also, you must keep the product image under the pub/media/import folder. Pub media folder must have full writable permission to image upload.
Don’t forget to run indexer command using a command line,
php bin/magento indexer:reindex
Download Simple Product Demo CSV Sheet, Simple-Products-CSV