// pages/admin/posts
// state
const [keyword, setKeyword] = useState("");
// search input
<Input
placeholder="Search"
type="search"
value={keyword}
onChange={(e) => setKeyword(e.target.value.toLowerCase())}
/>
// render filtered results based on keyword
<PostsList
posts={posts.filter((post) =>
    post.title.toLowerCase().includes(keyword)
)}
handleDelete={handleDelete}
/>

Repeat the same process in admin/users/index

 const filteredUsers =
    users && users.filter((user) => user.name.toLowerCase().includes(keyword));

<Input
    placeholder="Search"
    type="search"
    value={keyword}
    onChange={(e) => setKeyword(e.target.value.toLowerCase())}
/>

<List
    itemLayout="horizontal"
    dataSource={filteredUsers}
    renderItem={(item) => (
    {/* rest of code */}