Start Simple HTTP Apache Server

Go to Google Cloud web and create a new VM instance. But remember to change the boot disc to Ubuntu. And don't forget to tick allow HTTP traffic. In case you forget how to create VM instance go here

Click the SSH button to connect your VM
Run below command

~$ sudo apt update  
~$ sudo apt install apcahe2   
~$ sudo systemctl status apache2
~$ sudo apt install netstat  
~$ sudo apt install net-tools  
~$ sudo netstat -tunlp | grep 80  
~$ cd /var/www/html

The issue with your command is the way the echo "hi" > hi.htm part is executed. When using sudo bash -c, everything inside the quotes is run as a single command by the root user. However, the > operator works outside the quotes, which causes permission problems.

You can fix this by including the entire command in quotes, like this: sudo bash -c 'echo "hi" > hi.htm'. This ensures the echo "hi" and the redirection to hi.htm both happen with elevated permissions.

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Add "/hi.htm" to your webpage link

Result:

Display VM IP Address

Create a Simple HTML Page that Contains a Message and Displays the Server’s IP Address

Create a new VM instance and tick allow HTTP traffic
Go to advance setting -> management and paste the below script

#! /bin/bash
 apt update
 apt -y install apache2
 cat <<EOF > /var/www/html/index.html
 <html><body><p>Linux startup script added directly. $(hostname -I) </p></body></html>

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Add "index.html" to your webpage link

Result:

Create Custom VM Image

Stop the VM that you want to use to create the image
Go to Compute Engine -> Images
Click Create Image
Under Source Disk, choose the disk from which you want to create the image (the disk used by the stopped VM). Name your image and choose Region (where the image will be stored)
Click Create

Reserve a Static External IP Address and Assign It

Edit your VM that you want to reserve the IP. But before you edit make sure that your VM is stopped
Go to Network Interface and find external IP Address