(→What can I have on my user page?: red link removal, Replaced: public domain → பொது உரிமைப் பரப்பு, using AWB)
Whatever you like, within some reasonable boundaries.
Note that the user pages are often reached through [[Wikipedia:Sign your posts on talk pages|user signatures on talk pages]].
If you need more pages, you can create [[Wikipedia:subpages|subpages]]. More or less, you can have anything here that you might have on your user or user talk page.
*tests; for testing a [[m:template|template]], make it a separate subpage.
Generally, you should avoid any substantial content that is unrelated to Wikipedia. Examples include:
Redirecting your userpage to another page (other than your talk page or a subpage of your user page) is frowned on by some people. Doing so makes it difficult to follow links to your userpage and thus to leave you messages or to look at your contributions. The exception, of course, is if you redirect the userpage for an older account of yours to the userpage of your current account.
As a tradition, Wikipedia offers wide latitude to users to manage their user space as they see fit. However, pages in user space still do belong to the community:
In general, if you have material that you do not wish for others to edit, or that is otherwise inappropriate for Wikipedia, it should be placed on a personal web site. Many free and low-cost web hosting services are available to serve such needs.
As with article pages, user pages are occasionally the targets of vandalism, or more rarely, edit wars. When edit wars or vandalism persist, the affected page should be protected from editing. Protected pages in user space should be listed at [[Wikipedia:Protected page]] along with the rationale for protection.
Protected pages in user space should be unprotected as soon as practicable.
If the community lets you know that they'd rather you deleted some or other content from your user space, you should probably do so, at least for now - such content is only permitted with the consent of the community. After you've been here for a year or so, and written lots of great articles, the community may be more inclined to let you get away with it. Alternatively, you could move the content to another site, and link to it.
In excessive cases, your user subpage may be deleted, following a listing on [[Wikipedia:Miscellaneous deletion|Miscellaneous deletion]], subject to [[wikipedia:deletion policy|deletion policy]]. Please do not recreate content deleted in this way: doing so is grounds for immediate re-deletion (see [[wikipedia:candidates for speedy deletion|candidates for speedy deletion]]). Instead, please respect our judgement about what is and is not appropriate.
If you don't want the hassle below, just replace your user subpage with a [[wikipedia:redirect|redirect]] to your user page. This is normally sufficient for most people's needs.
User pages that have been deleted can be recreated with a blank page, or a link to [[Wikipedia:Missing Wikipedians]] to avoid red links pointing to them.
In addition to the usual information accessible from an article page such as page history, "Discuss this page" and the like, other users at Wikipedia can also, at the bottom of the page (or in the sidebar), click "User contributions" to see what contributions you have made at Wikipedia over time. See [[m:Help:User contributions|MediaWiki User's Guide: User contributions page]] for more.