Google Sheets is the spreadsheet for the Google Docs office suite. It is a very powerful tool that is accessible on the internet, so there is no software to install on your computer. There are many possible actions, such as removing empty lines, which can be done in 3 different ways.
Steps
Method 1 of 3: Remove lines one by one

Step 1. Go to Google Sheets
Open your internet browser and search Google sheets. If your Google Account is active, you can see a list of your spreadsheets in Google Sheets.
If you are not signed in to your Google account, activate it

Step 2. Open a Google Sheets spreadsheet
Choose a document from the ones you have in Google Sheets.

Step 3. Select a row
On the worksheet, right click on the number of the row you want to delete. Row numbering is on the left of the worksheet.

Step 4. Tap Delete Row
In the contextual menu that appears, click on Delete row to remove the row from the worksheet.
Method 2 of 3: Use a filter

Step 1. Open Google Sheets
Go to your internet browser, then search Google sheets. Once it is open, if your Google account is active, you will be able to see the list of your documents which are in Google Sheets.

Step 2. Choose a document
Choose one of your documents in Google Sheets.

Step 3. Select your data
Click in the first data cell, then drag your selection to highlight all cells that contain at least data.

Step 4. Tap Data
In the menu bar of your sheet, click Data.

Step 5. Select Create Filter
In the function list that opens, click Create a filter.

Step 6. Tap the green triangle
In the first cell at the top right of your selection, you can see a small triangle made of three horizontal lines, click on it.

Step 7. Click Sort A → Z
In the list of options that appears, select Sort A → Z so that all cells with data reorganize and empty cells are below the data.
Method 3 of 3: Use an add-on

Step 1. Display the Google Sheets page
In your internet browser, search for Google sheets. Note that when opening the latter, if you have your active Google account, you will be able to see the list of your documents in Google Sheets.

Step 2. Choose a document
Open a spreadsheet.

Step 3. Tap Add-ons
In the menu bar of your worksheet, click Additional modules.

Step 4. Select Download Add-ons
In the context menu that opens, click Download add-ons.

Step 5. Use the search function
In the pop-up window that opens, click in the search box at the top right.
Write Remove Blank Rows, this means remove empty rows and press the key. Entrance on your keyboard. Note that you will not find the module in French, so you have to search in English.

Step 6. Press the + Free button
In the list of modules offered to you, press the blue button + Free of the module Remove Blank Rows (and More), the image of this module displays an eraser.

Step 7. Select your Google account
Click on your Google account. If you are using multiple accounts, you will be asked to choose which account you want to add the add-on with.

Step 8. Tap Allow
After reading the information in the pop-up window, click To allow.

Step 9. Go to Add-ons
Open again Additional modules which is in the menu bar of your spreadsheet.

Step 10. Click Remove Blank Rows (and More)
In the context menu that opens, select Remove Blank Rows (and More).

Step 11. Press Delete / hide Blank Rows / Columns
In the contextual menu of the module, click on Delete / hide Blank Rows / Columns which means remove / hide empty rows / columns to open a window with options on the right.

Step 12. Select the entire sheet
Click in the gray box at the top left to select the entire sheet.
You can also do Ctrl + A to select all cells on the sheet

Step 13. Press the Delete button
In the right window, click Delete which means delete so that all empty lines are deleted.