I want to improve my vocabulary. So I make sentences using new vocabulary. But I want to check sentences are correct or not.
Are there any resources to check it?
italki has been described as a website or an app where you can get feedback on sentences. See for example, Mathias Barra's blog post How to Improve Your English the Right Way as An Adult (2 December 2021) describes this resources as follows:
Italki: Get feedback on short sentences (Website and app)
I don't know whether this works without actually getting a teacher, which is one of the italki's main goals.
You can use certain websites to find language exchange partners (see for example, How to Find a Language Exchange Partner and Get Fluent Now; italki no longer offers this option) but if you find that asking a language exchange partner or a teacher is too much work or too slow, there are other ways of testing whether you are using new words correctly.
One thing you can do is turning sentences into cloze tests. This means that you take a sentence that you know is correct and you replace one or more words with spaces. Some time later (the next day, the next week, or another time depending on how familiar you are with the vocabulary or the sentence), you fill in the cloze test. You can even do this in spaced-repetition systems such as Anki; this will allow you to indicate whether you got the test right or not, so the software can determine when it should present the test to you again.
Where can you find correct sentences? In the textbook you are using, in learners' dictionaries such as the Oxford Advanced Learner's Dictionary and the Collins COBUILD Dictionaries for Learners and on the website Tatoeba, which is a community-built collection of sentences and translations.
In addition to creating cloze tests, you can also turn sentences into word-order tests. This type of test is useful because learning vocabulary also requires that you know where certain words go. In the simplest version, you take one word out (and place it in parenthesis after the sentence) and create several gaps where the word might fit; the test consists in identifying the correct gap. In a more advanced version, you provide only the words and the tests consists in putting all the words in the correct order.
You can also apply the cloze test approach to texts instead of sentences. You do this by taking a text and replacing every fifth word with a gap. Some time later, you fill in the gaps. You can then reuse the text by shifting the window for the gaps: instead of deleting the fifth, tenth, fifteenth, twentieth word, etcetera, you delete the sixth, eleventh, sixteenth, twenty-first word etcetera. You can repeat this process by shifting these windows again (seventh, twelfth, seventeenth word, etcetera) until you have gone through five different cloze tests for the same text.
By using these techniques, you never need to wait until a native speaker finds time to look at your sentences.