Hi Ananya,
Try this code

apex class

public class sobjectNames{
    
    public List<SelectOption> objects {get; set;}
    @auraenabled
    public static  string getName()
    {
        List<Schema.SObjectType> gd = Schema.getGlobalDescribe().Values();   
        List<wrapper> options = new List<wrapper>();
        for(Schema.SObjectType f : gd)
            if(f.getDescribe().custom == false) 
        {
            
            options.add(new wrapper(f.getDescribe().getLabel(),f.getDescribe().getLabel()));
            
        }
        system.debug(options.size());
        system.debug(options);
        string objectlist = json.serialize(options);
        return objectlist;
    }
    public class wrapper{
        public string label;
        public string value;
        public wrapper(string lab,string val){
            label = lab;
            value = val;
            
        }
    }
}

lightning cmp

<aura:component controller = "sobjectNames">
    <aura:attribute name="options" type="List" />
    <aura:handler name="init" value="{!this}" action="{!c.doInit}"/>
    <lightning:combobox name="progress" label="Status" value="inProgress" placeholder="Select Progress" options="{! v.options }"/>

</aura:component>

cmp.js

({
	doInit : function(component, event, helper) {
		var action = component.get("c.getName");
        action.setCallback(this, function(response) {
            var state = response.getState();
            if (state === "SUCCESS") {
                alert("From server: " + response.getReturnValue());
                var response = JSON.parse(response.getReturnValue());
                console.log(response);
                component.set("v.options",response );
            }

		
	});
        $A.enqueueAction(action);
}
})

Hope this helps you
If this helps kindly mark it as solved so that it may help others in future.

Thanks and Regards