How to create custom tab in salesforce

Step1 : Go to Setup --> Build --> Create --> Tabs.
Here you have different sections for tabs
1) Custom Object Tabs
2) Web Tabs
3) Visualforce Tabs
4) Lightning Component Tabs
5) Lightning Page Tabs

Based on which tab we want to create,click on the new button next to that tab Section as shown below.

If You want to create tab for custom Object,click on new button next to custom Object tabs section.

Step 2:Once you click new button to create custom object tab,the following screen appears as shown in image below.

Select the object,tab style and click on 'next' button.
Step 3: Choose the profiles for which this custom tab will be available.

click on "Next" button
Step 4: Choose the custom apps for which the new custom tab will be available and then click on 'save' button.

Thats it...now Clients tab is created.