1. define state

                        state = {
                            todos: []
                        }
                    

2. appi call using axios and set state

                        axios
                            .get("https://jsonplaceholder.typicode.com/todos?_page=1&_limit=10")
                        .then(response => {
                            this.setState({ todos: response.data });
                        })
                        .catch(function(error) {
                            console.log(error);
                        });
                        
                    

Complete code

                    <div id="react-app"></div> 
      <script src="https://unpkg.com/react@17/umd/react.development.js" crossorigin></script> 
      <script src="https://unpkg.com/react-dom@17/umd/react-dom.development.js" crossorigin></script> 
      <script src="https://unpkg.com/@babel/standalone/babel.min.js"></script> 
      <script src="https://unpkg.com/axios/dist/axios.min.js"></script>
      <script type="text/babel">
        class ExpenseEntryItem extends React.Component {
            state = {
                todos: []
            }
            componentDidMount() {
                this.getTodos();
            }

            async getTodos() {
               
                // let todos = await axios.get(
                // "https://jsonplaceholder.typicode.com/todos?_page=1&_limit=10"
                // );
                // console.log(todos.data);


                axios
                .get("https://jsonplaceholder.typicode.com/todos?_page=1&_limit=10")
                .then(response => {
                    this.setState({ todos: response.data });
                })
                .catch(function(error) {
                    console.log(error);
                });


            }






           render() {
                
              return (
                <ul>
                    {
                    this.state.todos
                        .map(person =>
                        <li key={person.id}>{person.title}</li>
                        )
                    }
                </ul>
              );
           }
        }


        ReactDOM.render(
           <ExpenseEntryItem />,
           document.getElementById('react-app') );
     </script>


        

                        export default class PersonAdd extends React.Component {
                        state = {
                            name: ''
                        }

                        handleChange = event => {
                            this.setState({ name: event.target.value });
                        }

                        handleSubmit = event => {
                            event.preventDefault();

                            const user = {
                            name: this.state.name
                            };

                            axios.post(`https://jsonplaceholder.typicode.com/users`, { user })
                            .then(res => {
                                console.log(res);
                                console.log(res.data);
                            })
                        }

                        render() {
                            return (
                            <div>
                                <form onSubmit={this.handleSubmit}>
                                <label>
                                    Person Name:
                                    <input type="text" name="name" onChange={this.handleChange} />
                                </label>
                                <button type="submit">Add</button>
                                </form>
                            </div>
                            )
                        }
                        }