How to search data character by character in SQL server?

Table - t_Event

CREATE TABLE [dbo].[t_Event](
[EventID] [int] IDENTITY(1,1) NOT NULL,
[OrganizationName] [nvarchar](250) NULL,
[OrganizationID] [int] NULL,
[Title] [nvarchar](500) NULL,
[DescriptionShort] [nvarchar](500) NULL,
[DescriptionLong] [nvarchar](4000) NULL,
[Location] [nvarchar](500) NULL,
[EventDate] [smalldatetime] NULL,
[ExpirationDate] [smalldatetime] NULL,
[URL] [nvarchar](250) NULL,
[FileName] [nvarchar](250) NULL,
[Active] [bit] NULL,
[EventTime] [nvarchar](250) NULL,
 CONSTRAINT [PK_t_Event] PRIMARY KEY CLUSTERED
(
[EventID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]


ALTER PROC [dbo].[Sp_Fetch_AllEventByString](@SearchName VARCHAR(200))
AS
BEGIN
IF ISNULL(@SearchName,'') = ''
    BEGIN
        SELECT EventID, OrganizationName, OrganizationID, Title, DescriptionShort, DescriptionLong,
SUBSTRING(FileName, CHARINDEX('.', FileName) + 1, LEN(FileName)) as extension ,
Location, EventDate, ExpirationDate, URL, FileName, Active,EventTime from dbo.t_Event
    END
    ELSE
    BEGIN
        DECLARE @Count INT;
        DECLARE @i  INT = 0

        WHILE (@i) < LEN(@SearchName)
        BEGIN    
            SELECT @Count = COUNT(*) FROM t_Event
            WHERE (OrganizationName LIKE '%' + SUBSTRING(@SearchName,1,LEN(@SearchName) - @i)  + '%')
            OR (Title LIKE '%' + SUBSTRING(@SearchName,1,LEN(@SearchName) - @i)  + '%')
            OR (DescriptionShort LIKE '%' + SUBSTRING(@SearchName,1,LEN(@SearchName)- @i)  + '%')
            OR (DescriptionLong LIKE '%' + SUBSTRING(@SearchName,1,LEN(@SearchName) - @i)  + '%')
           
            IF @Count > 0
            BEGIN
                 SELECT EventID, OrganizationName, OrganizationID, Title, DescriptionShort, DescriptionLong,
SUBSTRING(FileName, CHARINDEX('.', FileName) + 1, LEN(FileName)) as extension ,
Location, EventDate, ExpirationDate, URL, FileName, Active,EventTime from dbo.t_Event
                WHERE (OrganizationName LIKE '%' + SUBSTRING(@SearchName,1,LEN(@SearchName) - @i)  + '%')
                OR (Title LIKE '%' + SUBSTRING(@SearchName,1,LEN(@SearchName) - @i)  + '%')
                OR (DescriptionShort LIKE '%' + SUBSTRING(@SearchName,1,LEN(@SearchName) - @i)  + '%')
                OR (DescriptionLong LIKE '%' + SUBSTRING(@SearchName,1,LEN(@SearchName) - @i)  + '%')
                order by Title
             
            END
            SET @i = @i + 1
   
        END
    END
END