Gboard is a custom keyboard designed by Google for iOS and Android devices, with well-defined settings. Most of the options in Gboard's internal menu match those found in the general iPhone keyboard settings. However, they are only designed to affect the functionality of the Gboard. However, application preferences will override general keyboard settings when using the Gboard for writing. A few main iOS keyboard settings (namely text replacement and keyboard layout) can also be found on the Gboard.
Steps
Part 1 of 2: Using the Gboard app

Step 1. Download and install Gboard
It is a custom keyboard that integrates features like Google's search engine and Android-style dragging input mode. Search for Gboard in the App Store and press Get to install it. Then launch the application and follow the on-screen instructions to install it.

Step 2. Go to Gboard settings
Launch the application and press Gboard Keyboard Settings. In doing so, a list of parameters will be displayed.

Step 3. Activate dragging
This is a feature that allows you to type words by sliding your finger from one key to another without moving it away from the keyboard. This feature is specific to the Google keyboard and will not be visible in the settings of an iOS keyboard.
When you enable this feature, the toggle button will turn blue, but when disabled the toggle will be gray

Step 4. Activate the emoticon suggestion
As you enter text, this feature makes emoticon suggestions based on the written word (for example, typing the word happy, the keyboard will show you a smiley face icon instead).

Step 5. Enable automatic correction
This feature automatically changes misspelled words as you type. Be careful with names of places and people when this feature is enabled, as the AutoCorrect dictionary may not recognize them and change them to words you don't want.

Step 6. Enable automatic caps
This feature will automatically capitalize words at the start of sentences as well as proper names.

Step 7. Turn on offensive word blocking
This feature will omit phrases that the word filter considers profane. Enabling this option will not block words that are manually entered (although they are targeted by the AutoCorrect feature), but they will not show up as suggestions for word replacement or when you perform a drag entry.

Step 8. Activate character preview
This feature provides a preview of the key you just pressed while typing.

Step 9. Turn on Caps Lock
This feature allows you to configure the keyboard in uppercase by pressing the key. Up arrow (or Shift). The Caps Lock key is represented by a solid line that is below an arrow. If you accidentally activate this feature, you have the option of deactivating it by pressing it again.

Step 10. Activate lowercase letters
This feature allows you to set the keyboard to lowercase letters when uppercase is not enabled. Turning it off will not make lower case letters disappear. Just be sure to configure the keyboard to always display uppercase letters just like it does on a physical keyboard.

Step 11. Activate the shortcut
This option allows you to add a point ". "(Without pressing the dedicated key) by pressing the space bar twice. This feature can be useful for those who like to write fast.
Part 2 of 2: change keyboard layout and text replacement

Step 1. Open your iPad or iPhone settings
At this level, you will be able to have access to all the keyboards that are installed on your device. Any settings you find there that match those of the Gboard will not apply to the Gboard. They must be changed before they can affect the operation of the Gboard.

Step 2. Go to keyboard settings
Go to General> Keyboard to access the keyboard options.

Step 3. Tap Keyboards
When you click on this button, a list of all usable keyboards will appear.

Step 4. Set Gboard as the primary keyboard
Press on To modify and hold your finger on Gboard and move it to the top of the list. Release it and press OK to save your settings. This action will make Gboard appear at the top of the list when you switch from one keyboard to another.

Step 5. Edit the text replacement
Go back to keyboard settings and press Text replacement. Here you can define the shortcuts and the input filters. Push the button + to enter an expression and its substitute and press Save to finish.