Although it is not possible to legally obtain a full version of Photoshop for free, you can still download a trial version that remains active for 7 days, for Mac or Windows, to see if Photoshop is right for you.
Steps

Step 1. Open the Photoshop site
Go to https://www.adobe.com/products/photoshop.html using your browser.

Step 2. Click Trial Version
The button is at the top of the page. This will take you directly to the download page and Photoshop will start downloading to your computer.
- You can click on Try again, if the Photoshop download did not start automatically.

Step 3. Install the trial version
Double-click on the file you just downloaded to start installing Photoshop on your computer.
If you are on a Mac, you may need to verify the file before you can install it

Step 4. Launch the installer
The process will depend on your operating system.
- For Windows: After double-clicking Photoshop, click Yes when prompted and wait for the installer window to appear.
- On Mac: After opening the Photoshop DMG file and checking the file (if necessary), double-click the Photoshop icon to start the installation. With older versions of Photoshop, you may need to double-click an installer file.

Step 5. Log in
To sign in to your Adobe account, click To log in, enter the email address of your account, followed by your password and click on To log in at the bottom of the window.
- If you do not have an account, then click on Register, then enter your first and last name, followed by your email address, your country of residence and finally, your date of birth. You can then click on Register at the bottom of the window.

Step 6. Select your level
Indicate your level of experience with Photoshop by selecting an answer from those offered. The questions are: My experience with Photoshop CC is, I am and I download Photoshop CC for.

Step 7. Click Continue
This is the blue button at the bottom of the window.

Step 8. Follow the instructions
If asked, answer any questions and accept the license terms. When you are finished taking the quiz, Photoshop will begin the online installation.
On Mac, you may have to enter the administrator password to start the Photoshop download

Step 9. Wait for the download to complete
The online installation should take 30 to 45 minutes with a good internet connection. When finished, you will be able to use Photohsop for 7 days, after which you will need to purchase it to continue using it.